Geographic Minerals

Daubréeite is a rare bismuth oxohalide mineral with formula BiO(OH, Cl). It is a sulphide of chromium observed in some meteoric irons. It is a…

Datolite is a calcium boron hydroxide nesosilicate, CaBSiO4(OH). It is a popular mineral among mineral collectors although it is somewhat obscure. It was first observed…

Danburite is a calcium boron silicate mineral with a chemical formula of CaB2(SiO4)2. It is a mineral consisting of a calcium borosilicate that is transparent…

Danalite is an iron beryllium silicate sulfide mineral with formula: Fe2+4Be3(SiO4)3S. It is beryllium-bearing, and found typically in tin-beryllium skarns, but also found in NYF…

Coltan (short for columbite–tantalites and known industrially as tantalite) is a dull black metallic ore from which the elements niobium and tantalum are extracted. The…

Clinochrysotile is a soft, fibrous silicate mineral in the serpentine group of phyllosilicates, also called “white asbestos”. It is a monoclinic form of Chrysotile. It…

Cleveite is an impure radioactive variety of uraninite containing uranium and found in Norway. It has the composition UO2 with about 10% of the uranium…

Citrine is a variety of quartz whose color ranges from a pale yellow to brown due to ferric impurities. It is a glassy yellow variety…

Chrysoprase is a gemstone variety of chalcedony that contains small quantities of nickel. It is an apple-green gemstone consisting of a variety of chalcedony that…

Chlorastrolite (also known as Isle Royale Greenstone), is a green or bluish green stone. It is named from Greek “chloros” – green, and “astros” –…

Chiastolite is a variety of the mineral andalusite with the chemical composition Al2SiO5. It is a form of the mineral andalusite containing carbonaceous inclusions giving…

Chalcedony is a translucent variety of quartz of various colors and waxy luster. It is a cryptocrystalline form of silica, composed of very fine intergrowths…