The main varieties of garnet

The main species
Purple teeth black deposits in a H&X Carborundum Abrasives of native , mainly produced in many magmatic or metamorphic rocks , the majority of gem garnet found in alluvial placer . Purple teeth black garnet group minerals , chemical composition is more complex silicate minerals ( island silicates ) , usually A3B2 [SiO4] 3 said . Where A represents Ca2 +, Mg2 +, Fe2 +, Mn2 + and other divalent cations , B represents Al3 +, Fe3 +, Cr3 + and other trivalent cations . Crystal morphology was rhombic dodecahedron , or both H&X garnet sand three octahedral poly shape. Granular or massive aggregates . Affected by the composition of the garnet color , showing a variety of colors , which include red red series ' Pink ' purple ' orange ; yellow line includes yellow ' orange ' dense yellow' brownish yellow ; green line includes green ' olive ' yellow and green . Crystal display glass glossy surface , sub- adamantine luster , fracture noticeable oil sheen . Transparent to translucent . Homogeneous body , does not have pleochroism , no birefringence . Garnet can be divided into two series , six main varieties : almandine series ( pyrope , almandine , spessartine ) and andradite series ( uvarovite , grossular , andradite ) .