Red Oxide of Titanium—Rutile

These specimens are from Cairngorum in Scotland, and I feel much gratified that there is added to British Mineralogy before it is finished another appearance and locality of so rare a substance that was not much known even in foreign countries. Many persons possess fine specimens of Quartz containing rod needle-like crystals of Titanium and long angular empty spaces, which, by their form, are now known as I laving probably once contained this substance; but these specimens are mostly foreign.

The upper specimen seems to have been part of an exposed vein in Micaceous Schist, and the Quartz is curiously distinguished by a certain ruggedness, perhaps owing to exposure, which gives it a roughish opacity outside, although it is very transparent and pellucid immediately beneath, holding long straight thin bars of Titanium in various directions, mostly separate, and of irregular forms: they are of an opaque brownish red or bright red according to the position of the light, reflexion, or fracture. The Quartz has a more milky appearance, and is destitute of Titanium in the interior.

The lower specimen has a large proportion of Titanium, in bars an inch or more long, so crowded as to give the whole a brow n red appearance, being about half Titanium; the rest. Quartz with some vestiges of the Micaceous Schist.