| Alabastron |
 |
A small, elongated bottle or flask for
holding ointments, perfume or oil.. |
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| Alcaline |
|
Containing alkali. Body showing the properties
or some of the particular properties of alkali, mainly
its faculty of becoming neutralized with acids.
Applicable to five metals that form a family and which
are, in order of increasing atomic number: lithium, soda,
potassium, rubidium and caesium. |
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| Alchemy |
|
In Julius Firmico’s astrological treaty
dating back to the IV century, the word alchemy was used
for the first time in reference to the metallurgic techniques
of the Egyptians and Sumerians who, since 4000 BC, were
able to obtain copper from malaquite.
One of the first known alchemy works is the treatise of
Physica et Mystica, attributed to the Egyptian Bolos de
Mende who lived on the Delta-Nile around 200 years BC.
The treatise is part of a compilation carried out in the
VIII century which includes Zozimo’s works, who lived
at the beginning of the Christian era.
After the conquest of Alexandria in the year 642, the
knowledge of Greek and Egyptians alchemists was added
to that of the Arabs.
In the XII century developed in Europe great interest
for alchemy and as a result of the translations of the
works of Arab alchemists, Europeans became familiar with
the new knowledge which would be the bases for what is
today known as chemistry. |
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| Alkali |
|
(Soda) Alkalis are chemical compounds widely
distributed in the vegetal kingdom which outstand for
the intense effects produced in the organism.
There are about 1,000 known alkalis, most are produced
by plants. Even though found throughout the plant, its
concentration is specially high in seeds, leaves, skin
and roots.
Chem. – name given to metal oxides highly soluble
in water that may act as strong bases.
Alkalis, bases or hydroxides have the fundamental quality
of releasing hydroxyl anions (or hydroxyl) HO and of combining
with acids producing salts vs. Base.
In glassmaking it is a soluble salt which main components
are potassium carbonate or sodium carbonate. Essential
ingredient for glassmaking, usually 15% – 20% is
needed in the batch.
Fixed alkalis such as soda and caustic potash stand out
from volatile alkalis, such as ammonia.
Salty base, similar to alkali and artificially obtained
from combinations of organic origin. Its industrial applications
are many. In large, most alkalis are found as organic
acids salts or, even more rarely, in mineral acids from
the vegetal kingdom, particularly in fruits and flowers. |
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| Alkali weed |
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Plant growing in Egypt and Malta along
the Mediterranean shores. The ashes obtained by leaching
are know as la rochelle. |
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| Alkalimeter |
|
Instrument of measure used to find the
amount of alkali in soda and potash carbonates. |
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| Amalgam |
|
An alloy of mercury with another metal;
gold for gilding glass; tin as mirrors backing. It was
used in the XIX century as glass for mirrors and for Christmas
ornaments. |
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| Annealing |
|
The process of subjecting glass to gradual
and uniform cooling in an anneling kiln.
After being formed, glass objects are annealed to relieve
stresses built up within the glass as it cools (see Annealing).
In an oven called a lehr, the glass is reheated to a temperature
high enough to relieve internal stresses and then slowly
cooled to avoid introducing new stresses. |
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| Aventurine |
|
Translucent glass with sparkling inclusions
of gold, copper, or chromic oxide, first made in Venice
in the XVII century and specially in the XVIII and XIX
centuries. |
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| Barilla |
|
Marine plant from the Mediterranean region
which was used as a source of soda. |
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| Blowing |
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The process of shaping a mass of molten
glass by blowing air through a metal tube into the mass
attached at its end. Technique used since the first century
BC.
Glass can be blown keeping the gob on the air or putting
it in a two piece mold or even in a mold of several pieces
with reliefed motifs. |
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| Calcedonio
Glass |
|
Calcedonio (Italian, "chalcedony")
Glass marbled with brown, blue, green, and yellow swirls
in imitation of calcedonio. Fabricated in Venice around
the year 1500 and later in 1700. In the XVII and XVIII
centuries a marbeled red glass was fabricated in Bohemia.
It was used again in the second half of the XIX century. |
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| Calcedony |
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A translucent to transparent milky or grayish
quartz with distinctive microscopic crystals arranged
in slender fibers in parallel bands.
its main varieties are: agate, carnelian and chrysoprase.. |
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| Calcite |
|
(Ca) Chemical element from the alkali-earth
family.
It is one of the most abundant element on earth’s
crust, mainly found as carbonate (calcite and limestone),
sulphate (chalk), fluoride (fluorite), and phosphate. |
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| Calcium |
|
With lime content. Sedimentary rocks primarily
made up of calcium and magnesium carbonates.
Contains calcium carbonate (Ca CO3). |
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| Cameo engraving |
|
Engraving with low relief to show the design
and background in contrasting colours. This type of work
required the use of a machine runned by water. This technique
was known in Egypt and was used to brand seals and in
gem cutting.
Cameo glass Overlay acid-etched in cameo style in England
at the end of the XIX century. Glass of one layer covered
usually by casing with one or more layers of contrasting
color(s).
The outer layers are acid-etched, carved, cut, or engraved
to produce a design that stands out from the background.
The first cameo glasses were made by the ancient Romans.
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| Casing |
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Glassware made by two or more layers of
different colours. A technique whereby glass of one colour
is fused onto the inner surface of glass of a different
colour, using a performed ‘cup’ of one colour
and introducing into it a glass of a different colour.
By repetition, a multicoloured layered glass can be produced. |
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| Ceramics |
|
Clay craftsmanship. The art of elaborating
earthenware and other clay items, tableware and porcelain.
Considered as scientific knowledge from an archeological
point of view. |
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| Clay |
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Clay, a natural, earthy, fine-grained material
occurring naturally from the weathering of rocks, thus,
with no specific chemical formula. Clays are fine grained,
generally in the size range of less than 0.004 mm (0.00015
in), with most grains less than half this size. If the
grains are larger in size it is called slime.
The clay minerals are hydrous silicate minerals, some
of them with magnesium or iron replacing aluminum totally
or partially, alkali and alkaline earth compounds, as
well, always made up of fine grained particles.
Clay minerals occur naturally from the weathering of rocks
and are components of argillaceous deposits, bentonite,
industrial vermiculite, etc.
All of them belong to the phyllosilicate mineral group,
clustering according to the stratus nature and the manner
it compounds to the structure. Its properties are linked
to the structural scheme of each group.
Clay is a fine-grained rock that, when adequately grinded
or powdered, becomes plastic when dampened and acquires
the consistency of hide when dry, when fired becomes a
permanent rocky mass. (American Ceramic Society).
Clay is the resulting product of earth’s aging process.
Material of natural origin, occurring naturally from the
weathering of rocks. Clay has no specific formula and
all existing types are a mixture of minerals with a high
share of ‘clay minerals’ such as kaolinite. |
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| Cobalt Glass |
|
Blue coloured glass obtained by the use
of cobalt oxide. Europe main cobalt deposit is found in
the Metalliferous mountains. In Venice, glassmakers started
using cobalt in the XV century. |
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| Cristallo |
|
Cristallo (italian).
A type of soda glass developed in Venice, perhaps before
the XV century. |
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| Crizzling |
|
Chemical deterioration of glass due to
the effects of moisture.
Solid crystal mineral which atoms or molecules have a
definite, orderly atomic structure and an outward form
bounded by smooth, plane surfaces, symmetrically arranged.
Crystallized variety of colorless, transparent quartz
used as precious stone and in the fabrication of optical
and electronic instruments. |
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| Cutting (graving) |
|
Process of cutting into glass surface by
the use of a rotating wheel of iron or stone of different
shapes and sizes. Using an abrasive material (damp sand,
emery) between big wheels rotating horizontally faceting
can be obtained. Small wheels of different shapes rotating
vertically are used to cut motifs. The shape of the wheels
can be flat, convex, or mitered. This technique was taken
from stone cutting techniques from ancient times. |
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| Cylinder glass |
|
Same as Broad Glass. Flat pane Glass made
by the process of blowing a large glass bubble and swinging
it on the blow pipe to form a long bottle and cutting
off both hemispherical ends. |
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| Daumenglas |
|
XVI century German drinking glass decorated
with circular indentations and usually also with bands
of encircling trailing above and bellow the indentations. |
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| Devitrification |
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Occidental process of converting glass
into a crystalline substance with a milky appearance. |
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| Diamond-Point
Engraving |
|
The technique of decorating glass by engraving
using a diamond or metal point to scratch the surface. |
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| Double Glass |
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Double walled glass decorated with an engraved
gold and silver leaf in between sealed with a colourless
resin to protect the design. |
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| Enamel |
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A pigment of vitreous nature coloured with
metallic oxides and an iron rich glassy frit, fused into
the glass surface by low temperature firing. Enamel colours
may be opaque or transparent. Enameling has been known
since the Roman Egypt and was later used on Islamic glass.
Enamels which melt at high temperatures (750 – 900ºC)
are the best for obtaining bright, shining colours. Powdered
pigment can be stenciled or applied diluted in water on
the glass surface.
A vitreous substance made of finely powdered glass colored
with metallic oxide and suspended in an oily medium for
ease of application with a brush. The medium burns away
during firing in a low-temperature muffle kiln at about
500° to 700° C (965°-1300° F). Sometimes,
several firings are required to fuse the different colors
of an elaborately enameled object. |
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| Enameling |
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A low-temperature firing of clay earthenware
in the muffle kiln, to affix permanently the shine and
luster of glass. |
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| Engraving
|
|
Embossing or debossing onto a surface.
The process of cutting into the surface of an annealed
glass object either by holding it against a rotating copper
wheel fed with an abrasive or by scratching it, usually
with a diamond. |
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| Etching |
|
Decoration on the surface of glass by the
use of hydrofluoric acid to etch the exposed design into
the body of the piece on the areas not covered with an
acid resistant barnish (wax, lacquer, oil). |
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| Faenza |
|
Ravenna, Italy. Ceramic production center
since the XIV century |
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| Faience |
|
A ware made in Egypt known as “thehent”
by ancient Egyptians and which means ‘shiny or glittering’.
It is a vitreous paste made up by grind-quartz frit with
small quantities of natron, lime and plant ashes.
Glass paste made up by grind -quartz frit with small quantities
of natron, lime and plants ashes.
Also known as Egyptian ware. |
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| Faienza |
|
Ceramic object covered with glaze and coloured
with enamel, such as that made in Italy, similar to Egyptian
faience. |
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| Feldspar |
|
Mineral group chemically constituted by
soda, potassium, calcium and barium aluminosilicates.
Feldspars are the most abundant and widespread minerals
of Earth’s lythosphere.
Feldspars are also major constituents of igneous and metamorphic
rocks. They are used as raw material in the ceramic industry.
A very high percentage of the rocks forming earth’s
crust are “feldspathides” such as granite, that
is, having a variable content of a mineral called feldspar
which in time becomes kaolin deposits due to the effects
of water.
Feldspathides Mineral group chemically composed by sodium
aluminosilicate, potash and calcium differing from feldspars
by a minor silica content, such as lapis lazuli. |
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| Fern Glass |
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Greenish tinted glass made since the Middle
Ages. The green colouring comes from an alloy of iron
and impure potash. |
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| Filigrana |
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Venetian or Venetian style glass.
Literally, thread grained. Decorated by the use of opaque
white or coloured glass threads in lace-like or crisscross
patterns. |
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| Flint |
|
.Common term for silex.
Fine grained silica rock, hard and compact, mostly constituted
by calcedony (quartz) of variable colors occurring as
nodules, hard mass or fine layers inside limestone (chalk)
and dolomites.
Prehistoric people used it for the making of weapons and
utensils. |
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| Frit |
|
Vitrifyable mix, pre-heated in a calcar
but not completely melted or fused.
Sand and alkali additives mix that, after being partially
fused and then cooled, is ground into a powder to be added
to the final ingredients that go into the pot, to be melted
into glass. Used in making of enameled and moulded glass. |
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| Galena |
|
Mineral pigment used as eye cosmetic. |
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| Gilding |
|
The process of decorating glass by the
use of gold leaf, gold paint, or gold dust. The gilding
may be applied with size, or amalgamated with mercury.
It is then usually fixed to the glass by heat. Gold leaf
may be picked up on a gather of hot glass. Gilding can
be applied in hot or cold techniques. In hot gilding,
gold chloride is dissolved in boiling distilled water,
an amalgam of gold and mercury can also be used. In cold
gilding gold it is fixed with flaxseed oil. |
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| Glass |
|
(Si O2) (Ca) (Na)
An amorphous, artificial, non-crystalline substance made
by fusing some form of silica and an alkali and sometimes
another base such as lime.
Material obtained by the overcooling of an homogeneous,
massive, fused substance formed by silica, lime and soda.
When hot it is soft, easy to work with, thus, ductile.
It is transparent or translucid and hard, fragile to changes
in temperature. Resistant to most reactive agents.
Chemically speaking, glass, in its purest form, is silicon
anhydride or silica which means that every molecule is
formed by an atom of silicon and two atoms of oxygen.
Silica can be sand, quartz crystals or flint. |
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| Glass Paste |
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Mix of grind glass, flux and metal oxides
fused in a mold. |
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| Glaze |
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Vitreous polish, used for clay or earthen
ware. |
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| Grisaille |
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Decorative painting on glass used since
the Middle Ages to define details and shades in stained
glass windows. |
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| Hand barrow |
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Arms of the chair used by the gaffer where
he rests the blowpipe with its parison of molten glass
and rolls it backward and forward during the forming process. |
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| Hot Glass |
|
Glass formed by blowing or moulding and
decorated by trimming, nipping by adding canes
or inlaid motifs. |
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| Hyalith glass |
|
A dense opaque glass, coloured- sealing
wax red or jet black. It is obtained by different means,
especially by manganese saturation. Usually decorated
with golden figures. |
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| Ice Glass
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Ice Glass A decorative technique whereby
the surface of the glass is deliberately made rough and
opaque, like cracked ice by plunging a paraison of soft
glass into cold water early in the blowing process so
that the surface is fussed. After gently reheating, the
final blowing enlarges the web of cracks to create a frosted
appearance. |
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| Inlay |
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Inlay Annealed relives, elements incorporated
to glass by fusing. Inlays may be golden or coloured.
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| Iridescence |
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Most of the time natural iridescence is
due to oxidation. Artificial oxidation can be obtained
by the action of metallic oxides fumes in a medium heat
kiln. |
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| Isotropic |
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Identical in all directions; invariant
with respect to light direction. |
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| Kaolin |
|
Calcium carbonate mineral (Ca CO3)
Colorless, white or of different colors. Quite abundant
on earth’s crust.
White colored clay which main component is basically kaolinite.
Used extensively in ceramics for the making of porcelain
objects.
Deposits of pure mineral occur in China, England; and
North Carolina in America. |
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| Kaolinite |
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(Ca O) Caustic lime, gray or grizzly adulterated
by clay, iron oxides and magnesium. |
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| Lead crystal
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|
The lead content in this glass (24 to
30%) reduces and eases the fusing point. This type of
glass is soft, shiny, heavy and is particularly suited
for decoration by cutting. |
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| Limestone
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Calcium carbonate rock (CaCo3). |
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| Limy |
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(Si4O10 (OH)8 Al4) Aluminum phyllosilicate.
Type of feldspar. Main kaolin ingredient. |
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| Lithyalin
glass |
|
A polished opaque glass marbled on the
surface in red and other strong colors. |
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| Luster |
|
Metallic pigments that after firing in
a reduction unit, produce iridescence on the surface of
glass. This type of glass decoration was made in Egypt
between the IX and XI centuries. |
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| Mass decorated
glass |
|
Technique whereby molten glass is blown
into a mould carved with relieves, then blown a second
time to attenuate those relieves so that the motif will
appear shadow like. |
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| Metal |
|
Simple substance, of a particular shine,
high specific weight, good heat and electricity conductor;
in general, ductile and malleable.
Chem.: Physically, the main characteristic of metals is
their metallic shine, a group of mechanical qualities
such as hardness, toughness, ductility and malleability.
Classification of metals according to Thénard y
Regnault: lithium, soda, potassium, rubidium, caesium
(alkaline metals), magnesium, manganese, aluminum, beryllium,
iron, cobalt, chrome, zinc, cadmium, tin, antimonious,
wolfram, lead, copper, bismuth, mercury, silver, gold,
platinum.
It is also possible to obtain alloys among these metals
which result in various products suitable for diverse
uses. |
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| Milk and Water
Glass |
|
Opaque, white glass, couloured with ashes
from calcinated bones or with tin-oxide or eventually
with antimony. Name given to filigree when worked in the
glass blowing technique. |
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| Millefiori
Glass |
|
A style of decorating glass with slices
of opaque coloured canes embedded in a colourless molten
glass mass. |
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| Mineral |
|
Natural inorganic solid matter with a
definite, orderly atomic structure.
It may or may not form crystals of different size, ranging
from invisible to the human eye to measuring even more
than a meter in width in diameter. Mineral species are,
as a rule, of definite chemical composition and with a
determined crystalline structure that sometimes occur
in geometric like shapes. Minerals must fulfil three requirements:
material unit, natural origin and belong to the solid
layer of earth's crust.
Mineral matter is formed by the systematic arrangement
of the constituent particles, atoms, ions or molecules,
which originate a regularly homogenous crystalline matter
that, if occurring in a polyhedron shape, forms a crystal.
In general, any naturally occurring chemical element or
compound, but in mineralogy and geology, chemical elements
and compounds that have been formed through inorganic
processes. More than 3000 mineral species are known, most
of which are characterized by definite chemical composition,
crystalline structure, and physical properties.
They are classified primarily by chemical composition,
crystal class, hardness, and appearance (color, luster,
and opacity). Mineral species are, as a rule, limited
to solid substances, the only liquids being metallic mercury
and water. All the rocks forming the earth's crust consist
of minerals.
Metalliferous minerals of economic value, which are mined
for their metals, are known as ores.
Homogeneous portion of matter that has a definite, orderly
atomic structure, and an outward form bounded by smooth,
plane surfaces, symmetrically arranged. Crystals are produced
whenever a solid is formed gradually from a fluid, whether
the formation results from the freezing of a liquid, the
deposition of dissolved matter, or the direct condensation
of a gas into solid form. The angles between corresponding
faces of any two crystals of the same substance, regardless
of size or superficial difference of form, are always
identical |
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| Mineral |
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Produced by rolling the hot glass globe
over a marble or iron plate covered with small pieces
of coloured glass. These pieces adhere to the surface
of the globe resulting in a geometrical design or scenes
with characters. |
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| Mosaic glass |
|
(Produced by rolling the hot glass globe
over a marble or iron plate covered with small pieces
of coloured glass. These pieces adhere to the surface
of the globe resulting in a geometrical design or scenes
with characters. |
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| Natron |
|
(CO3 Na2) Sodium carbonate.
The best known natron resource is found in Wadi Natrum
in the Lower Egypt, finding also great deposits in Elkelab
in the High Egypt. These deposits are gathered in banks
along the shores of the ancient lakes which are mentioned
since the Pharaohs’ era. For thousands of years it
was used for embalming by the Egyptians. |
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| Obsidian |
|
From the Latin obsidianus lapis, a natural
glass of volcanic origin of varied chemical composition,
usually shiny black in color with metallic reflections.
One of the materials used the most by ancient man for
the elaboration of weapons and utensils.
Term used to specify glass of volcanic origin, usually
of rhyolitic composition, formed by the rapid cooling
of molten igneous rock where its constituent ions did
not have the necessary conditions to group in defined
interatomic structures and crystallize. Hardness of 5.5
according to Mohs scale. |
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| Opal
Or Opalescent Glass |
|
One of the procedures for the
making of this glass is by adding bone powder to the mix.
Opal glass was highly valued in Bohemia and France where
opal crystal and glass were made. Now a days it is known
as “opalescent.” Said of any glass into which
a material has been introduced at the raw materials stage
(usually fluorine or phosphorus) |
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| Polyhedron |
|
In geometry, a solid bounded by flat surfaces
with each surface bounded by straight sides. Each of the
flat surfaces is called a face.
A convex polyhedron is one in which a line segment connecting
any two vertices of the polyhedron contains only points
that are on a face or inside the polyhedron. Otherwise,
it is called concave.
In a regular polyhedron all of the faces are regular polygons
that are congruent (equal in size and shape). |
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| Pontil |
|
The pontil, or punty, is a solid metal
rod that is usually tipped with a wad of hot glass, then
applied to the base of a vessel to hold it during manufacture.
It often leaves an irregular or ring-shaped scar on the
base when removed. This is called the "pontil mark." |
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| Porcelain |
|
A hard, white, translucent ceramic made
by firing kaolin, quartz and feldspar. |
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| Potash Glass |
|
Potash is used as fusion agent in the
making of this type of glass. Potash is obtained by leaching
wood ashes, evaporating the lye, and calcinating the residue. |
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| Pottery |
|
Clay craftsmanship |
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| Precious Stone
Engraving |
|
Engraving on glass surface by the use
of wheels and abrasives, such as abrasive wheel, silicon
carbide powder, diamond powder, pumice powder. |
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| Pressed Glass |
|
Semi-automatic fabrication by using several
metalic moulds and a press machine. Glassware formed by
placing a blob of molten glass in a metal mould, then
pressing it with a metal plunger or "follower"
to form the inside shape. The resultant piece, termed
"mould-pressed," has an interior form independent
of the exterior, in contrast to mould-blown glass, whose
interior corresponds to the outer form. The process of
pressing glass was first mechanized in the United States
between 1820 and 1830. |
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| Quartz |
|
(Si O2 ) Silicon dioxide crystallizing
in the trigonal system. It is the most abundant mineral
on earth’s crust, crystallizing in different shapes.
It is the primary element occurring in a large number
of magmatic, metamorphic or sedimentary rocks.
Quartz is colorless and transparent when pure. |
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| Rock |
|
Naturally occurring solid material consisting
of one or more minerals. |
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| Rock crystal |
|
Natural quartz which atoms or molecules
have a definite, orderly atomic structure and an outward
form bounded by smooth, plane surfaces, symmetrically
arranged. |
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| Ruby Glass |
|
Ruby-couloured glass obtained by adding
copper, gold or cadmium selenide. After a series of experiments,
since 1820, glass factories in Bohemia made Ruby glass
of compound properties, that is, mixed with lead. |
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| Sandwich Glass |
|
Double walled glass with inner decoration
of an engraved or painted metal leaf. |
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| Silica |
|
Silicon dioxide (SiO2) Mineral with many
cryptocristalline varieties (quartz, rock crystal, amethyst,
etc.) and amorphous (calcedony, jasper, agate, etc.)
Silica is the most abundant mineral on earth. In ancient
times, earth’s three great divisions were called
by their average chemical composition.
The crust was called SIAL (silica and aluminum); the stratum
was SIMA (silica and magnesium) and the core NIFE (nickel
and iron). When it is added but not consolidated it forms
silica sands but when consolidated forms rocks such as
quartz arenites, when containing other particles of rock
and other minerals; or quartzite when containing only
quartz.
It is found in a great quantity of minerals. It’s
a polymorphic body occurring in nature as quartz or crystal
rock, trydimite. |
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| Soda |
|
Soda hydroxide, White, glassy solid material
very soluble in water and alcohol. It is obtained by the
dissolution of sodium chloride by electrolysis. |
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| Soda-Lime
Glass |
|
Soda is commonly used as the alkali ingredient
of this type of glass. It is soft and easy to work in
a kiln. |
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| Sodium |
|
(Na) Chemical element belonging to the
alkaline family.
It is the sixth most abundant element on the earth’s
crust. Its most important salts are sodium chloride or
common salt, sodium carbonate, cubic niter and sodium
sulfate. It is a white, opaque, soft, ductile and chemically
active metal. |
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| Stained Glass
Window |
|
(leaded) Window glass composed of small
panels of dyed and painted glass, held in strips of cast
lead and mounted in a metal framework, used for doors
or windows. |
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| Stained-glass
Window |
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Glass frame for doors and windows made
of pieces of coloured glass fitted into channeled lead
strips. |
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| Staining |
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Silver or yellow Staining; the process
of colouring the surface of annealed glassware by the
use of coloured pigments, ochre and silver chloride that
merely sink into the surface leaving a yellow transparent
film. This technique has been used since the XIV century
mostly for stained-glass windows.
For copper or red staining, a mix of copper sulfate and
ochre is used which, after three distillations by a reducing
agent, produces a red glaze. |
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| Steatite |
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Talc variety made up by phyllosilicates
occurring in grey or green compact or finely scaly masses
which, when mixed with clay and feldspar forms a material
used in ceramics. |
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| Unguentarium |
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A small receptacle used in ancient times
for perfume. |
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| Vitrify |
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The process of changing certain materials
into glass or a glassy substance by heat or fusion. |
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| Vitrofusion |
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Vitrofusion technique relates to the fusing
compatibility between two types of glass. Vitrofusion
is a glassmaking technique by overlapping, folding, embossing
and colouring using ceramic oxides. This technique was
successfully carried out by the Egyptians in ancient times.
The stress meter verifies glass compatibility, which shows,
by a system of polarized lenses, the inner strains in
the finished piece: the more evident the strain, the more
fragile the glass. |
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