Allanite is a silicate containing a large amount of cerium. It is usually black in colour, opaque, and is related to epidote in form and composition. It occurs as a minor constituent of many igneous rocks and is frequently associated with epidote. Found in some magnetic bodies. It has the formulae (Ce,Ca,Y)2(Al,Fe)3(SiO4) 3(OH) and a relative hardness of 6. It is named after T. Allan who discovered it. Research Allanite
Epidote is a common mineral found in regional and metamorphic rocks of mafic composition and as a product of alteration of other minerals. It is sometimes used as a gemstone. It has the formulae Ca2(Al,Fe)3Si3O12(OH) and a relative hardness of 7. Research Epidote
Stilpnomelane is a mineral forming dark coatings in schist and may also be found in iron ore deposits, commonly associated with epidote and mica. Stilpnomelane was confirmed as a distinct species of mineral in 1827 but since then debate has raged as to whether it is a simple mineral or a mixture of closely related species. Stilpnomelane is a hydrous silicate of potassium, ferrous and ferric iron, magnesium and aluminium and has a relative hardness of 3 to 4. Pure
stilpnomelane contains more ferric iron than ferrous iron, specimens containing more ferrous iron then ferric iron are sometimes known as chalcodite or ferrostilnomelane. Research Stilpnomelane
Zoisite, named after its discoverer its discoverer, Von Zois, an Austrian mineralogist, is a greyish or whitish mineral allied to epidote, occurring in orthorhombic, prismatic crystals, also in columnar masses and formed in high temperature metamorphic rocks. It is a silicate of alumina and lime has the formulae Ca2Al3 (Si3O12)(OH) and a relative hardness of 7. Research Zoisite
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Matt and Leela Probert
Abbreviations
Research Allanite
