Glossary - Rarity4u

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Glossary of antique and collectable terms

There are 856 entries in this glossary.

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I

Term	Definition
Imari	Type of Japanese export porcelain made at Arita and shipped from the port of Imari. The typical red and underglazed blue colours and gilding were much immitated by 1700´s and 1800´British factories
Imperial Jade	Imperial jade is another name for emerald jade. It is a fine emerald-green colour
Imperial Mexican Jade	Imperial Mexican jade is not jade at all; it is calcite that has been dyed green
Imperial Topaz	Imperial topaz is golden orange-yellow topaz; it is the most valuable type of topaz
Inca Emerald	Inca emerald is an emerald that is mined in Equador
Inclusion	An inclusion is a particle of foreign matter that can be solid, liquid or gaseous, contained within a mineral. Many inclusions decrease the value of a stone, but some, like rutile forming asterisms in star sapphires and needles in rutilated quartz and tourmalinated quartz, increase the value of the stone.
Indian Agate	Indian agate is another term for moss agate
Indicolite	Indicolite is a green to blue-green variety of tourmaline
Ingot	Piece of cast metal obtained from a mould in a form suitable for storage.
Inlay	A furniture ornament of bone, mother-of-pearl, different coloured woods etc., set into the surface of a piece of furniture as decorative banding, patterns and designs. Much used on furniture of the later 1700's
Intaglio	Intaglio is a method of decoration in which a design is cut into the surface. Signet rings are frequently decorated with intaglio, as are seals
Intergrown	Intergrown crystals occur when two mineral crystals grow together and become one
Inverall Sapphire	Inverall sapphires are a type of sapphire from Inverall, New South Wales, Australia
Investment Compound	An investment compound is a refractory material that can withstand extreme heat, which is slightly porous so that gases from molten metal can escape and can be formed into a mould which will be used in metal casting. An example of an investment compound is plaster of paris mixed with silica, boric acid, and graphite
Invisible Necklace	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
Iolite	Iolite, also known an water sapphire, is a transparent, violet-blue, light blue, or yellow-grey mineral. Iolite is pleochroic; a single stone will show many colours (in the case of Iolite, violet-blue, light blue, and yellow-grey). Iolite is found in Sri Lanka, India, Madagascar and Burma. Iolite is not rare and has a hardness of 7 - 7.5
Iridescent	An iridescent object displays many lustrous, changing colours. Iridescence is caused by the reflection of light from the jewel
Iridium	Iridium is a metal related to platinum. Iridium and platinum are frequently alloyed together, since the iridium increases the workability of the platinum. Iridium is also used for the points of gold-nibbed pens
Irradiated Diamonds	Irradiated diamonds are diamonds that have been exposed to radiation. This changes the diamond's colour because the radiation changes the crystalline structure of the diamond and 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-particles 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 colour; 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 colour change.
Irradiation	Irradiation is the act of being exposed to radiation. Many stones like kunzite are irradiated in order to enhance their colour. Being irradiated changes the crystal structure of the mineral by moving electrons. Irradiation techniques bombard the crystal with high-energy radiation like gamma rays, producing a stone with very little radioactivity and a change of colour. Some colour changes caused by Irradiation are permanent, others are unstable and can be reversed by heating or exposure to sunlight. For example, colourless topaz changes to a cinnamon brown colour after being irradiated with cobalt-60 radiation, but the colour fades as the stone is exposed to sunlight. A new method of irradiation changes clear topaz to a brilliant, non-fading blue