Holmquistite

Holmquistite is a lithium magnesium aluminium inosilicate mineral with chemical formula: Li2(Mg,Fe)3Al2Si8O22(OH)2. It crystallizes in the orthorhombic crystal system as prismatic crystals up to 10 cm (3.9 in) or as massive aggregates. It has a Mohs hardness of 5-6 and a specific gravity of 2.95 to 3.13.