Oxide of Manganese

Manganese is found in the neighbourhood of the Mendip Hills in Somersetshire, and about Bristol; also hollow stones of various sizes which include various substances as well as Manganese. See tab. 405. The present specimen is a hollow nodule of Quartz inclosing spicule of a mixture of Oxide of Iron with a little Manganese. I have seen some that show by the form of the crystal that they are chiefly Manganese. These, however, are more of an ochraceous or yellow brown colour, something like the usual Oxide of Iron. The form of these spiculæ is mostly flatten four-sided columns; they are laminated in their structure, the laminaæ formed as it were of still smaller laminæ; two opposite edges are sometimes replaced by little truncating planes. The pyramids depend upon the spiculated crystals protruding in various lengths pyramidally. The vacancy between the quartzose crystals allowed some of them to shoot more or less regularly, and the more solid Quartz and Carbonate of Lime do not seem to interrupt them: we therefore see the beautiful ordering of Nature is such that, neither interrupts the other. Manganese is generally present where there is a crimsonish hue given to substances. The outside is chiefly Quartz approaching Chalcedony. Sometimes these stones are nearly of a vermilion red colour outside.