A Lithium Aluminum silicate with formula: LiAlSiO4 and hardness 6.5.
Always massive, rarely transparent,more often translucent like in this case here. Rarely cut a a gem it shows a moderate blue-violet fluorescence at short wave UV light sometimes in bright pink-red.
This gem comes from Australia.
Size: 10.2x9.2x6 mm.
Weight: 3.60 ct.