Interference quartz
Mineralogical designation for quartz with interfered or inhibited growth (irregular shapes and partial crystal planes). “Interference” in quartz can result from several mechanisms. The growth…
Category: Gem or Scam? Library
(Imperial) Mexican Jade
Misleading commercial name for green dyed (!) calcite or so-called onyx marble. No relation to jade except the similarity in color, but jade sells better…
Indigo gabbro
Commercial name for a gray, violet translucent gabbro rock speckled with black, usually in the form of spheres, sculptures or tumble stones. Although still touted…
Iris agate
Name for an iridescent variety of agate. Agate consists of so-called fibrous chalcedony. In thin slices, the fibers are sometimes visible in transmitted light and…
Iris quartz
Fantasy name for natural quartz in which rainbow colors occur due to refraction of light on internal fracture surfaces. This effect is also called iridescence,…
Isis calcite™
A commercial, unregistered trade name for a calcite native to the Sahara Desert. The material offered under this name is usually light yellow in color.…
Jacaré quartz
Name used for a growth form of quartz (usually smoky quartz) with many parallel crystal faces (bulges or intergrowths). Named after the Portuguese word “jacaré”…
Jade
The name jade is unfortunately common in this library. Jade has traditionally been a beloved and valuable ornamental stone. By using the name for similar…
Jadine
Misleading commercial name for Australian chrysoprase (a green variety of chalcedony). So again, this is not real jade, but the name is used to better…
Jasper
Mineralogical name for a variety of chalcedony, which in turn is a microcrystalline variety of quartz. Geologically, the name has long been used for an…
