GROUTITE
GROUTITE Groutite – Mn3+O(OH) – is a very rare oxide. It integrates Mn ores, but generally occurs sporadically. It can form larger volumes, but it is never the main ore mineral in the deposit. It is classified in the Diaspora Group, with which it is isostructural. It is a polymorph of feitknechtite and manganite. May […]
GEOCRONITE
GEOCRONITE Geocronite – Pb14(Sb,As)6S23 – is a rather rare sulfosalt associated with Pb-As-Sb-S parageneses. It occurs in polymetallic ores but is never the primary ore mineral of the deposit. It is classified within the Jordanite Homologous Series Group, being isostructural with and forming a series with jordanite. 1. Characteristics Crystal system: Monoclinic prismatic. […]
GUDMUNDITE
GUDMUNDITE Gudmundite – FeSbS – is a fairly rare sulfide and, for that very reason, is not considered an ore. It belongs to the Arsenopyrite Group and may contain Ni. It is an alteration product of tetrahedrite (“fahlore”). 1. Characteristics Crystal system: Monoclinic prismatic. Color: Steel gray. Habit: Prismatic, in columnar […]
GEDRITE
GEDRITE Gedrite – Mg2(Mg3Al2)(Si6Al2)O22(OH)2 – is a rare amphibole, characteristic of very specific metamorphic parageneses. It is not an ore. Gedrite is classified in the Gedrite Group, which consists of gedrite and ferrogedrite. The two extreme terms of the Group are rare; variable contents of Mg (gedrite) and Fe (ferrogedrite) generally occur. Gedrite forms a […]
GREENOCKITE
GREENOCKITE Greenockite – CdS – is a rare sulfide. It is the only ore mineral of Cd, but Cd is obtained as a by-product in the mining of Pb, Zn, and Cu. Greenockite was used as a yellow pigment until it was recognized that Cd is very toxic. It is classified in the Wurtzite Group, […]
GUMMITE
GUMMITE “Gummite” is the name given to a mixture of uraninite and secondary uranium minerals of variable composition. This mixture is composed of uraninite remnants mixed with boltwoodite, clarkeite, curite, kasolite, soddyite, and uranophane. Sometimes the material has the appearance and consistency of rubber, and the name comes from this: “Gummi” means rubber in German. […]
GIBBSITE
GIBBSITE Gibbsite – Al(OH)3 -is a very common hydroxide, an important component of soils and one of the minerals that make up laterites and bauxites, which are aluminum ores. Gibbsitic clays are also interesting for the manufacture of refractory materials. Gibbsite, also called hydrargillite, has the polymorphs bayerite, doyleite and nordstrandite and a basic mica […]
GARNIERITE
GARNIERITE Garnierite, an important nickel (NiO) ore, is not a single mineral, but a generic, “umbrella” term for a mixture of varying shades of green of more than six different hydrated phyllosilicates of Ni and Mg. This mixture includes two or more of the following minerals: serpentine, talc, sepiolite, smectite, chlorite, and vermiculite. In addition, […]
GERSDORFFITE
GERSDORFFITE Gersdorffite – NiAsS – is a relatively rare sulfide. It is possible that it was not detected in many occurrences due to its similarity to galena and other ores. Integrates polymetallic ores. It is classified in the Cobaltite Group which, except for cobaltite itself, is made up of rare and extremely rare minerals. It […]
GYPSUM
GYPSUM Gypsum – CaSO4.2H2O – is the most common sulfate, one of the most abundant minerals in evaporite rocks. It is a very important ore for plaster, mineral fillers, fertilizers, and much more. It is classified in the Gypsum Supergroup, being isostructural with ardealite, brushite, and pharmacolite. It can dehydrate to bassanite at high temperatures. […]