Botryoidal Oxide of Iron. Hæmatites

Nothing but specimens or figures can give an idea of some of the works of creation; and the form it are often entirely out of the reach of many, either from local rarity, expense, room, and many other reasons. Who indeed would have guessed, from the best or most elaborate description, the absolute form of this Iron Ore, that bad not seen the like? I therefore consider the specimen, although a variety, as of some consequence; and it is even geologically instructive. That the rounding form is so usual is a subject to speculate upon; and the manner of radiation in every Hæmatite, from the smallest to the largest, is undoubtedly characteristic, as well as crystallization; although perhaps somewhat inferior, as not being so distinctly understood. Observation and experience will, however, by degrees, enable us to comprehend it as a leading character of some substances, in a specific way.

The Pisolites, Oolites, &c., as they are sometimes called, are as yet but vaguely understood, and cause much confusion. It is therefore necessary that we should be guarded against deception in rounded forms, particularly as there is perhaps scarcely one substance that has not a variety partaking of it.

Mr. Herbert is to be thanked for this specimen, who brought it from Downsend, near Bristol, and was so good as to present it to me in 1808. The green iridescence on the left hand upper corner, he observed, was beautifully striking in some specimens.