Eucryptite
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Eucryptite is a lithium bearing aluminium silicate mineral with formula LiAlSiO₄. It crystallizes in the trigonal – rhombohedral crystal system. It typically occurs as granular to massive in form and may pseudomorphically replace spodumene. It has... Wikipedia
Formula: LiAlSiO4
Color: Brown, colorless, white
Crystal class: Rhombohedral (3); H-M symbol: (3)
Crystal habit: Rare as euhedral crystals, coarse crystalline aggregates and massive
Crystal system: Trigonal
Density: 2.67
Mohs scale hardness: 6.5