Additional Jewelry Terms and Definitions
AMBER
Amber is fossilized tree resin that comes in many
colors, including yellow, red, white, black, and blue.
Rubbing amber produces static electricity. The word
electricity comes from the Greek word for amber, "elektron."
It used to be thought that amber possessed magical powers
that protected the wearer from evil. Pressed amber
consists of small pieces of amber that have been fused
together to form a larger piece. Fake amber is easily made
from plastics, and buyers must beware of cheap imitations
sold as natural amber. Amber has a hardness of 2.5 and a
specific gravity of 1.05-1.10.
AMETHYST
Amethyst (Greek for "not drunken") is a form of
the mineral quartz, and is a relatively common gemstone.
Amethyst is usually purple, but can range in color from
pale lavender to a very deep, reddish purple to a milky
color to green. Deeper-colored amethysts are more highly
valued. The ancient Greeks believed that amethyst made one
immune to the effects of alcohol. Synthetic amethysts are
hard to distinguish from the real stone.
CONCH
Conch is a marine animal (a mollusk) with a large,
beautiful pearly shell that varies in color, but if often
white or pink (pink is the most valued color). Queen conch
has a large, pink shell. Conch shell is often used to make
jewelry. Conch is made into beads and cameos. Conch has a
hardness of 2.85 (it is relatively soft).
CUBIC
ZIRCONIUM
Cubic zirconium (also known as cubic zirconia) is an
inexpensive, lab-produced gemstone that resembles a
diamond. Cubic zirconia was developed in 1977.
EMERALD
Emeralds are a very hard, green precious stone (beryl,
Be3Al2Si6O18, colored by chromium and some vanadium
impurities). Flaws and cloudiness (called jardin) are very
common in emeralds, so many emeralds are oiled,
irradiated, and dyed to improve their look. Synthetic
emeralds (developed by Carroll Chatham in the 1930's) have
fewer imperfections and are very hard to distinguish from
natural emeralds. Emeralds belong the beryl group of
stones which also includes aquamarines, morganite, and
chrysoberyl). Emeralds have a hardness of 7-8 and a
specific gravity of 2.6 - 2.8. Emerald (and all forms of
beryl) have large, perfect, six-sided crystals. Emeralds
were long thought to have healing powers, especially for
eyesight. During the renaissance, emeralds were used as a
test for friendship among the aristocracy; an emerald
given to a friend would remain perfect as long as the
friendship endured.
FOSSILIZED
IVORY
This material affords the same flexibility as deer or elk
antler for the very same reasons. Most fossilized ivory
originate from Alaska in the form of walrus teeth or
ancient mammoth tusk
FRESHWATER
PEARL
A freshwater pearl is a pearl that was harvested from a
freshwater mussel (a mollusk). These pearls are frequently
shaped like crisped rice cereal, and are less valuable
than oyster pearls. Biwa pearls are very good quality
freshwater pearls.
GARNET
Garnets are any of a group of semi-precious silicate
stones that range in color from red to green (garnets
occur in all colors but blue). Some garnets used as
gemstones include pyrope (the deep red garnet), almandine,
spessartine, grossular, the iron-aluminum dark red garnet
(also known as the carbuncle stone), Uvarovite (rare), and
the lustrous Andradite (which includes the valuable green
demantoid garnet, Topazolite , and Melanite). Red garnet
is the birthstone for January. Garnet has a hardness of
6-8 and a specific gravity of 3.5 - 4.3. The formula for
garnet is: (Mg, Fe, Ca or Mn) with Al2Si3O12.
GEMSTONE
A gemstone (also called a precious stone) is a mineral
that is valuable, rare and often beautiful. A few organic
materials, like amber, coral and pearls are also
considered gemstones.
HAMMERED
METAL
Hammered metals have been formed, shaped, or decorated by
a metalworker's hammer. The surface of hammered metal is
covered with crater-like depressions made by a hammer.
Many hammered metals are used in jewelry including gold,
silver, brass, aluminum, etc.
HEAT
TREATMENT
Heat treatment is the heating of stones to a high
temperature in order to enhance the color or clarity. For
example, blue-green aquamarine becomes blue with heat
treatment and brown zircon becomes blue or clear.
INLAY
An inlay is a piece of material (often stone or glass)
that is partially embedded in another material (usually
metal) such that the two materials make a level surface.
IRIDESCENT
An iridescent object displays many lustrous, changing
colors. Iridescence is caused by the reflection of light
from the jewel.
LAB
RUBY (SAPPHIRE)
A lab ruby (or sapphire) is a synthetic (laboratory-made)
stone. It has the same composition, hardness, and specific
gravity as natural rubies (or sapphires) but is much less
expensive than a natural stone (since they are relatively
inexpensive to create in the laboratory as compared to
mining gemstones). These lab-produced stones can be
legally referred to as "real" stones [as opposed
to "natural" (mined) stones].
LUSTER
A stone's luster is its sparkle or sheen - the way it
reflects light. The luster depends on the nature of the
stone's surface reflectivity. Some types of luster
include: adamantine (also called brilliant or diamond
like, like a faceted diamond), earthy (with little
reflectivity- also called dull, like shale or clay),
greasy (like nepheline or apatite), metallic (also known
as splendent, like pyrite or marcasite), resinous (like
amber), pearly (with an iridescent reflectivity, like
pearls or mica), pitchy (tarry minerals that are
radioactive, like uraninite), silky (with a fibrous
structure, like some tiger's eye or satin spar), vitreous
(also known as glassy, like olivine, transparent quartz,
or obsidian), and waxy (like halite or turquoise). A
pearl's luster is derived from its nacre.
ONYX
Onyx is a semi-precious stone that is black and white,
generally arranged in layers. It is a form of agate with
parallel banding. This structure lends itself to cameo
making. Onyx is a species of chalcedony (microcrystalline
quartz).
OPAL
Opals are semi-precious stones that are luminous and
iridescent, frequently with inclusions of many colors
("fire"). Opal is a mineral composed of
noncrystalline (amorphous) silica (and some water) and is
a species of quartz. There are three major types of opals:
common opal, opalescent precious opal (white or black,
with a rainbow-like iridescence caused by tiny crystals of
cristobalite), and fire opal (a milky stone that is firey
orange to red in color with no opalescence). Contra luz
opals are transparent opals that show a brilliant play of
iridescence only when light shines through the stone. Many
opals have a high water content - they can dry out and
crack if they are not cared for well (opals should be
stored in damp cotton wool). Some opals are treated with
oil, wax or resin to enhance their finish. Opals have a
hardness of 5.5 to 6.5 and a specific gravity of
1.98-2.50. Opals are found in many places worldwide,
including Kenya, Czechoslovakia, Brazil, Peru, Honduras,
Mexico, Canada, and the USA -- but Australia has a
tremendous variety of beautiful opals.
PERIDOT
Peridot is a yellow-green semi-precious stone with an oily
luster; peridot is a transparent, green form of olivine.
Peridot exhibits double refraction; when you look through
the stone, things appear double. For example, when looking
into a faceted peridot gemstone, the number of bottom
facets appears to be double the actual number of facets.
Most peridots are from a volcanic island in the Red Sea,
Zebergit/St. John, the "Serpent Isle." Peridots
have been found in meteorites. Peridot has a hardness of
6.5. Peridot cat's eye also exists.
PLATING
Plating or electroplating (also called Galvanotechnics
after its inventor, Luigi Galvani) is a process in which
one metal is coated with another metal using electricity.
In jewelry, inexpensive metals are frequently
electroplated with more expensive metals, like gold (gold
plating), copper (electrocoppering), rhodium (rhodanizing),
chromium (chromium plating), or silver (silver plating).
The thickness of the metal coat varies. Electrogilded
coating is the thinnest (less than 0.000007 inches thick);
gold-cased metals have a coating thicker that 0.000007
inches.
POROUS
Porous stones have tiny holes in them. These holes allow
water, oils, and other substances to penetratethe stone,
frequently changing their appearance over time. Many
stones are porous, including turquoise.
RUBY
Rubies are precious stones and a member of the corundum
family (Al2O3). Rubies range in color from the classic
deep red to pink to purple to brown. Rubies are extremely
hard; only diamonds are harder. During the renaissance,
people thought that rubies could counteract poison.
Laboratory-produced rubies were created in the 1890's;
they are difficult to distinguish from natural rubies. The
biggest ruby in the word is the Raviratna, which weighs
3,600 carats. Rubies have a hardness of 9 and a specific
gravity of 3.9 - 4.1. Rubies are found in Afghanistan,
Australia, Brazil, Cambodia, India, Myanmar (Burma),
Malagasy Republic, Malawi, Pakistan, Sri Lanka (Ceylon),
Tanzania, Thailand, United States, and Zimbabwe
(Rhodesia).
SAPPHIRE
Sapphire is a precious gemstone (a type of corundum) that
ranges in color from blue to pink to yellow to green to
white to purple (mauve sapphire) to pink-orange (padparadscha
sapphire). Six-sided asterisms sometimes occur in star
sapphires (caused by inclusions of tiny, thin, parallel
needles of rutile). Sapphires are related to rubies.
Sapphires were once thought to protect the wearer from
poisonous creatures. Sapphire has a hardness of 9 and a
specific gravity of 3.9 - 4.1. Sapphires are often heat
treated to improve their color.
SETTING
A setting is a method of securing a stone (or other
ornament) in a piece of jewelry (or other object). There
are many different types of settings, including the collet
(a strip of metal surrounding the stone), the claw setting
(in which prongs of metal hold the stone in place),
Tiffany (a high, six-pronged setting), the cut-down
setting (metal is worked around the edge of the gem,
reinforced with metal ridges), pavé-set stones (stones
set close together, showing no metal between them),
millegrain (the stone is secured by small beads [grains]
of metal), gipsy setting (with a recessed stone), and many
other types (including combinations of the above-mentioned
methods). Some settings are closed (there is metal behind
the stone), while others are open (there is no metal
behind the stone), letting light shine through the stone.
SILVER
Silver is a fine, silver-white metal often used in
jewelry. Pure silver has a hardness of 2.5. Other metals
are alloyed with silver (usually copper) for silver used
in jewelry making. Silver tarnishes after exposure to air
(a thin layer of silver-oxide forms on the surface).
Silver often occurs near copper lodes.
SPINEY
OYSTER
Spiney Oyster, Spondylus Brodnip Princess is found in the
Sea of Cortez, Baja California, Mexico. It appears in
lower Baja California Sur Mexico. It was discovered in
1976 and began to be exported for jewelry making use in
the Southwest by Indian Crafts people. The shell comes in
three colors red, orange, and purple sometimes yellow and
white. Spondylus Calcifer commonly called Giant Pacific
Rock Oyster is a purple that is found in water from 0-60
ft. After 60ft of water the white Spondylus appears and
goes down to 90ft of water. After 90ft of water the reds
and the oranges appear.
SYNTHETIC
STONE
Synthetic stones are made in laboratories; these stones
generally lack imperfections. It is very difficult to
distinguish a synthetic stone from a natural stone.
TOPAZ
Topaz (aluminum silicate fluoride hydroxide) is a very
hard gemstone that ranges in color from brown, to yellow
to blue to pink. Pink topaz is usually created by
irradiating common yellow topaz. Other colors are often
created by heat-treating and/or irradiating topaz.
Imperial topaz is golden orange-yellow topaz; it is the
most valuable topaz Topaz has a hardness of 8 and a
specific gravity of 3.5-3.6. Topaz may have been named for
the legendary Topasos Island in the Red Sea.
TOURMALINE
Tourmaline is a dichroic gemstone that comes in many, many
different colors; it also appears to have different colors
depending on the angle at which it is seen. Tourmaline has
the greatest color range of any gemstone - the lighter
colors are more valuable than the darker colors. It ranges
in color from pink to green to red (rubellite) to purple
to blue-green (indicolite) to colorless (achroite) to
black. Watermelon tourmaline is both pink and green.
Tourmaline occurs as an elongate three-sided prism and is
mined in Brazil, The Ural mountains in Russia, Namibia,
Sri Lanka, and California. Tourmaline was only discovered
in the 1700's. Tourmaline has a hardness of 7-7.5 and a
specific gravity of 3.02-3.25. It is doubly-refractive.
TURQUOISE
Turquoise is a non-translucent, porous semi-precious stone
(it is a hydrated phosphate of copper and aluminum) that
is usually cut as a cabochon. Turquoise was believed to
have been first found in Turkey, hence its name (Turquie
is the French word for Turkey). The oldest turquoise mines
are located in Alimersai Mountain in Persia (Iran) and in
the Sinai Peninsula in Egypt. Turquoise is found in desert
regions worldwide. The finest turquoise is Persian
(Iranian) turquoise; it is robin's egg blue and has no
matrix (streaks of the mother stone from which they were
found). North American turquoise is greener and has a
matrix streaks. Over the years, oil from your skin is
absorbed by the stone and it will change color slightly.
Turquoise has a hardness of 6 and a specific gravity of
2.60-2.85. Turquoise is the national gemstone of Iran.
Turquoise is one of December's birthstones
ZIRCON
Zircon (zircon silicate) is a lustrous gemstone that comes
in colors ranging from golden brown to red to violet to
blue. Pure zircon is colorless, but most zircon stones are
brown. Zircon stones can be heat-treated to become blue or
colorless; sometimes, heat-treated stones revert to their
original color.
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