I.D. is short for "Identification", so an I.D. bracelet is simply
a curved plate engraved with the name or initials of the person wearing
Stands for the "International Gemological Institute". It is
the largest independent gem certification and appraisal service in the
A substance produced under conditions involving intense heat, such as
that which is found in volcanoes. Igneous rock is rock formed by solidification
from molten magma.
Imperial jade is another name for emerald jade. It is a fine emerald-green
Imperial topaz is golden orange-yellow topaz; it is the most valuable
type of topaz.
Imperial Mexican Jade
Imperial Mexican jade is not jade at all; it is calcite that has been
The act of bringing or carrying in goods from an outside source for trade
or sale, especially in regards to goods from a foreign country.
Inca emerald is an emerald that is mined in Equador.
A naturally occurring flaw, (feather, fracture, fissure, carbon spot,
or cloud), within a diamond or other stone. The test for clarity looks
for these flaws.
Indian agate is another term for moss agate.
Metal cast into a bar or other shape.
Past tense of inlay.
A decorative technique in which part of the surface of a piece of jewelry,
furniture, or ceramic is cut away and stone, mother of pearl, or some
other substance is imbedded into the hollowed-out area so that it is level
with the surface of the piece. See also channel inlay.
Italian for "carving", an Intaglio is a carved gem wherein the
design is engraved or carved into the object so that it sits below the
surface plane of the material, as opposed to a cameo in which the design
is raised from it's background, in relief. This technique was often used
for seals, which made a raised impression in wax used to seal a letter
or authenticate a document. It was commonly attached to watch fobs, since
the watch fob is a good manner of carrying a seal. Once seals fell out
of common use, the intaglio tended to face out to the viewer rather than
down as on a seal. Some of the most commonly found Victorian intaglios
were carved in carnelian, an orange-brown variety of chalcedony.
Intergrown crystals occur when two mineral crystals grow together and
Inverall sapphires are a type of sapphire from Inverall, New South Wales
An investment compound is a refractory material (it can withstand extreme
heat) which is slightly porous (so that gases from molten metal can escape)
and can be formed into a mold (which will be used in metal casting). An
example of an investment compound is plaster of paris mixed with silica,
boric acid, and graphite.
An invisible (or floater) necklace looks as though the beads are simply
floating on the skin; the beads or pearls are strung far apart from one
another on an almost invisible string (like clear fishing line).
A method of setting square gemstones side by side in two or more rows
within a metal border or frame so that they are flush against one another
with no metal separating them.
(also called dichroite or water sapphire). A silicate of alumina, iron,
and magnesia which is usually violet-blue, but can be deep blue, light
blue-gray, and yellow-white. Makes a beautiful transparent gemstone which
is remarkable for its dichroism.
A display of lustrous rainbow-like colors. The colors seen in an oil slick
or mother of pearl are good examples of iridescence. Synonymous with "Pearlescent".
A metal of the platinum family often alloyed with platinum to improve
workability. Pieces marked "80% Plat. 20% Irid" would indicate
that the alloy is 80 % platinum and 20% iridium.
Irish diamond is not a diamond at all; it is rock crystal from Ireland.
The most common metallic element which usually appears dark brown, from
oxidation or impurity, but when pure is silvery-white. Iron is found abundantly
in nature, usually in combined forms such as hematite, limonite, magnetite,
and taconite. It is frequently alloyed in a wide range of important structural
materials like cast iron, steel, and wrought iron. It is easily oxidized
(rusted) by moisture, and is attacked by many corrosive agents.
Irradiated diamonds are diamonds that have been exposed to radiation.
This changes the diamond's color (as the radiation changes the crystalline
structure of the diamond). The change in the diamond is permanent. Older
radiation treatments involving exposing the stone to radium; newer treatments
bombard the stone with atomic particles in a cyclotron (which accelerates
protons, neutrons, or alpha-partices to high speeds). The irradiated stones
take on a greenish or an aquamarine hue. Irradiations of diamonds was
first done in 1904 by Sir William Crookes, who exposed diamonds to radium,
giving them a permanent greenish color; his diamonds are still slightly
radioactive (at the level of radium-painted watch). Newer irradiation
techniques bombard the crystal with atomic particles in a cyclotron, and
then the stone is heated to about 800 degrees Centigrade, producing a
stone with very little radioactivity and a permanent color change.
The process of bombarding a gemstone with X-rays, gamma rays or streams
of subatomic particles in order to change the stone's color.
Italian lapis is not lapis; it is actually blue-dyed jasper from Italy.
See French Ivory.
A hard, smooth yellowish-white substance made from the tusks of elephants
See French Ivory.