1911 Encyclopædia Britannica/Strontianite

by Leonard James Spencer

STRONTIANITE, a mineral consisting of strontium carbonate, SrCO₃. It takes its name from Strontian in Argyllshire, where it appears to have been known as far back as 1764, but it was not recognized as a distinct mineral until later, when the examination of it led to the discovery of the element strontium. It crystallizes in the orthorhombic system and is isomorphous with aragonite and witherite. Distinctly developed crystals are, however, of rare occurrence; they are usually acicular with acute pyramid-planes and are repeatedly twinned on the prism. Radiating, fibrous or granular aggregates are more common. The colour is white, pale green or yellowish brown. The hardness is 31/2 and the specific gravity 3·7. Strontium is sometimes partly replaced by an equivalent amount of calcium. The mineral occurs in metalliferous veins in the lead mines of Strontium in Argyllshire, Pateley Bridge in Yorkshire, Braunsdorf near Freiberg in Saxony; abundantly in veins in calcareous marl near Münster and Hamm in Westphalia; and in limestone at Schoharie in New York. It is used for producing red fire in pyrotechny and for refining sugar.  (L. J. S.)