BARYTES, a widely distributed mineral composed of ba rium sulphate (BaSO,) . Its most striking feature and the one from which it derives its name barytes, barite (from the Greek (3apvs, heavy) or heavy spar, is its weight. Its specific gravity of 4.5 is about twice as great as that of salt and of many other colourless, transparent and glassy minerals not unlike barytes in general appearance. The min eral is usually found in a state of consider able chemical purity, though small amounts of strontium and calcium sulphates may isomorphously replace the barium sulphate.
Crystals of barytes are orthorhombic ; they are usually very perfectly developed and present great variety of form. The sim plest crystals are rhomb-shaped tables bounded by the two faces of the basal pinacoid (c) and the four faces of the prism (m) ; the angle between the prism-faces (mm) is 78° 23', while that between c and in is 90°. The mineral has a very perfect cleavage parallel to the faces c and in, and the cleavage surfaces are per fectly smooth and bright. The crystals may be transparent and colourless, or white and opaque, or of a yellow, brown, bluish or greenish colour. The mineral occurs also in a granular, earthy or stalactitic condition. It is known as "cawk" in the Derbyshire lead mines. Barytes is of common occurrence in metalliferous veins, especially those which yield ores of lead and silver.
Commercially, barytes is used in the preparation of barium compounds, as a body for certain kinds of paper and cloth and in gramophone records, as a white pigment ("permanent white"), and as an inert body in coloured paints.