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Amethyst. Amethyst is a violet variety of quartz. The name comes from the Koine Greek αμέθυστος amethystos from α- a-, "not" and μεθύσκω ( Ancient Greek) methysko / μεθώ metho ( Modern Greek ), "intoxicate", a reference to the belief that the stone protected its owner from drunkenness. [ 1]
Topaz is a silicate mineral made of aluminum and fluorine with the chemical formula Al 2 Si O 4 ( F, OH) 2. It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can make it pale blue or golden brown to yellow-orange. [7]
Howlite was discovered near Windsor, Nova Scotia, in 1868 by Henry How (1828–1879), a Canadian chemist, geologist, and mineralogist. [6] [7] How was alerted to the unknown mineral by miners in a gypsum quarry, who found it to be a nuisance. He called the new mineral silico-boro-calcite; it was given the name howlite by the American geologist ...
Ametrine, also known as trystine or by its trade name as bolivianite, is a naturally occurring variety of quartz. It is a mixture of amethyst and citrine with zones of purple and yellow or orange. Almost all commercially available ametrine is mined in Bolivia. The colour of the zones visible within ametrine are due to differing oxidation states ...
Jasper. Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases, [ 1][ 2] is an opaque, [ 3] impure variety of silica, usually red, yellow, brown or green in color; and rarely blue. The common red color is due to iron (III) inclusions. Jasper breaks with a smooth surface and is used for ...
Luminous gemstones. Folktales about luminous gemstones are an almost worldwide motif in mythology and history among Asian, European, African, and American cultures. Some stories about light-emitting gems may have been based on luminescent and phosphorescent minerals such as diamonds.
Azurite was known in the pre-classical ancient world. It was used in ancient Egypt as a pigment, obtained from mines in Sinai. Ancient Mesopotamian writers report the use of a special mortar and pestle for grinding it. It was also used in ancient Greece, for example on the Acropolis in Athens.
Coal – Combustible sedimentary rock composed primarily of carbon. Conglomerate – Sedimentary rock composed of smaller rock fragments. Coquina – Sedimentary rock that is composed mostly of fragments of shells. Diamictite – Type of sedimentary rock. Diatomite – Soft, siliceous sedimentary rock that is easily crumbled.