Phenakite
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Phenakite or phenacite is a fairly rare nesosilicate mineral consisting of beryllium orthosilicate, Be₂SiO₄. Wikipedia
Hardness: 7.5–8
Cleavage: Distinct on, imperfect on
Color: Colorless, yellow, pink, brown
Crystal class: Rhombohedral (3); H-M symbol: (3)
Crystal habit: Tabular, prismatic to acicular crystals often as columnar aggregates, as spherulites and granular
Crystal system: Trigonal