Liddicoatite
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Mineral NameLiddicoatite
Chemical FormulaCa(Li,Al)3Al6(Si6O18)(BO3)3(OH)3F
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavageindistinct
Fractureconchoidal
Specific Gravity3
Colorsyellow, brown, dark gray
Transparencytranslucent
Type LocalityMadagascar
Mineral GroupSilicates (Tourmaline Group)
Usesgemstone, collector's item
Associated Mineralsquartz, feldspar, lepidolite
Rarityuncommon
Description
A translucent slice of liddicoatite displaying striking triangular growth zoning in shades of yellow, brown, and dark gray, characteristic of its crystal structure.
Geological Context
Liddicoatite is a member of the tourmaline group, typically found in lithium-rich granitic pegmatites, often associated with other rare-element minerals. Its distinctive zoning reflects changes in fluid chemistry during crystal growth.
