Fluorite and Barite

Fluorite (CaF2) can come in a variety of colours from white to violet. Lustre is vitreous and streak is white. Hardness is 4 and cleavage is perfect in four directions forming an octahedron. Fluorite usually occurs as cubic or penetrations twins but can also be octahedral, dodecahedral, cleavage masses, granular or columnar. Barite (BaSO4) can be white, grey, colourless or shades of yellow, brown, red or blue. Lustre is vitreous or pearly and streak is white. Hardness is 3 to 3 1/2 and cleavage is perfect in one direction, good in a second direction and distinct in a third. Barite usually occurs as thin or thick tabular crystals but can be also prismatic, divergent group, compact, lamellar, fibrous or granular.