Barite and Calcite

Sample of yellow subhedral prisms/scalenohedrons of Calcite with one large brown euhedral prismatic Barite crystal embedded on the Calcite. Calcite crystals have a dull lustre and the Barite crystal has a vitreous lustre. Barite (BaSO4) is white, grey and colourless but can also come in variety 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 second direction and distinct in a third. Barite usually occurs as thin or thick tabular crystals but can also be prismatic crystals, compact, lamellar, fibrous or granular in form. Calcite (CaCO3) can be white, colourless, pale shades of grey, yellow, red, green, blue, brown to black when impure. Lustre is vitreous or dull and streak is white. Hardness is 3 and cleavage is perfect in three directions forming a rhombohedron. Calcite usually occurs a rhombohedrons, scalenohedron or prisms but can also be tabular, acicular, cleavable, granular, compact, stalactitic, oolitic or earthy.