Dolomite and Quartz

Grey Dolomite and white Quartz disseminated into one another. Dolomite (CaMg(CO3)2) can be white, colourless, pink, grey, green, brown or black in colour. Lustre can be vitreous or pearly and streak is white. Hardness is 3 1/2 to 4 and cleavage is perfect in three directions and forms a rhombohedron. Dolomite is usually rhombohedral with curved faces but can also be granular, compact, massive (Dolomite Rock) and cleavage masses. Quartz (SiO2) has a large variety of colours from white to purple. Lustre can be greasy or vitreous and streak is white. Hardness is 7. Quartz is usually found as short or long prismatic crystals that are terminated by double rhombohedrons. Quartz can also be granular, massive or disseminated.