Shungite
Name for a black, shiny, mineraloid: a solid in a rock that has no ordered crystal structure (so-called amorphous structure). The term shungite was originally…
Category: Gem or Scam? Library
Black amethyst
Trade name for a very dark, gray or smoky, amethyst. Sometimes it is a combination of smoky quartz and amethyst, but usually the color is…
Siberian blue quartz / Siberian Blue
Misleading commercial name for, in most cases, man-made, blue colored glass. This material has been on the market for years, but has recently become more…
Black labradorite
Synonym for larvikite, a magmatic rock (syenite or monzonite) from Larvik, Norway. Includes feldspars that show a Schiller effect (“labradorescence” or “adularescence”) similar to labradorite.…
Black moonstone
Commercial name for a dark gray to brownish-black, unspecified feldspar with a form of ‘flash’ or pearly luster. A rough piece of ‘black moonstone’ from…
Sulfur
Official mineral name for the element sulfur when it occurs as a natural mineral. It appears in a variety of forms: from powdery yellow layers…
Silicon carbide
Name for man-made compound of silicon and carbon (SiC), also known as carborundum and sometimes referred to as moissanite. There is a very rare natural…
Sulfur in quartz / sulfur quartz
Questionable name for yellowish colored quartz; the yellow color is probably caused by limonite or other iron compound, but not sulfur. Judy Hall introduces the…
Transvaal jade
Misleading commercial name for a massive variety of grossular, a green mineral from the garnet group. Named after the former Transvaal province in South Africa…
Swiss opal
Misleading commercial name for serpentine with chrysotile (a fibrous mineral from the asbestos group). Sometimes also offered as Zebra jasper, but this usually refers to…
