Barite
De Dictionnaire geolien
Sommaire
COLOR
Grey. Takes a rather good polish. No pleochroism.
REFLECTANCE
Very low. Strongly higher than quartz.
ANISOTROPISM
Not visible. Very abundant white or yellowish internal reflections.
TEXTURE
The mineral shows numerous cleavages. Thus triangular pits are quite common. Barite shows a strong tendency to develop idiomorphically and occurs as lamellae which are often radiating.
ASSOCIATED MINERALS
Galena, sphalerite, pyrite, chalcopyrite, bournonite, linneite, bravoite, silver minerals, quartz, fluorite.
CRITERIA OF DETERMINATION
The lamellar texture, triangular pits, reflectance slightly higher than quartz are characteristic. Also the softness which can be easily determined by scratching the polished section.
Source
ATLAS OF ORE MINERALS (P. Picot and Z. Johan)