2S0 PITCHSTONE FAMILY. This mineral has never been found in the Scandinavian Peninsula. It occurs in the Electorate of Saxonv, near Meissen, along with porphyry and sienite; in a similar formation at Braunsdorf, Spechtshausen and Mohorn, between Dresden and Ereyberg, and near Dittersdorf. A newer formation occurs at Planitz, near Zwickau, al so m Saxony *. The blue variety of pitchstone occurs near Vicenza in Italy, and probably in floetz-trap rocks f. Pitchstone occurs in porphyry of the second primitive formation between Schemnitz and Kremnitz, and also near Tokay in Hungary; and in several of the islands in the Mediterranean, it appears to be associated with por- phyry. ^ Asm. It occurs at Kolyvan in Siberia, and near Mur- sinsk, in the Uralian mountains. Amcria.—In Mexico, according to Sonnenschmidt, it occurs in great abundance, associated with clay-por- phyry. In South America it occurs at Pasto, Popayan, and Quito, along with clay-porphyry. Observations. 1. It has been confounded with Semi-Opal; but it is distinguished from it by the following characters: its co- lour-suite is more extensive, and the colours are duller, and more muddy than those of semi-opal: its lustre is vitreo-resinous; but that of semi-opal is vitreous: its fracture is imperfect conchoida!; that of semi-opal per fect * German mineralogist* have not hitherto ascertained the formation to which the Planitz pitchstone belongs. t In the Isle of Eigg, there is a blue variety of pilehstone, occurring id floetz-trap, which resembles that of Vicenza.
