Hæmatitic Oxide of Tin. Wood Tin
- Class 3. Metals.
- Order 1. Homogeneous.
- Gen. 5. Tin.
- Spec. 1. Oxide.
- Div. 2. Imitative.
- Fibrous Tin Stone, Wood Tin Ore. Kirw. 2. 198.
- Etain oxydé concrétionné. Haüy, 4. 147.
The peculiar hæmatitic structure of this Ore of Tin, or rather the radiated structure that often attends the Hæmatite or Iron Ores, having a woody appearance, has given rise to the name, which serves very well upon the whole, although we do not think it very apt, considering its hardness and specific gravity. In its usual state it may most readily be distinguished from Iron hy merely weighing it in the hand.
The upper specimen is magnificent as to size, being very rarely found half so large. It was lent me for this public use by Edward Hawkins, Esq., who possesses a fine assortment, and is inferior only to one in the Greville collection.
The right hand lower specimens are of the most usual size; the left hand one shows the concentrating radii with the outer coat bubbled as it were, and according with the general appearance of the upper specimen.
It is perhaps an extraordinary circumstance that this substance is not known to be attached to any rock, and it was once thought that only one or two specimens were to he found in which it was attached, Mr. Day thought he had one, which I now possess) but I find that its supposed great value now only consists in its being that identical specimen; for, upon examining it particularly, I find it has only the characters belonging to Iron Hæmatites, viz. that of being soft enough to show the streak upon being scratched, and which is red, whereas the Wood Tin should not vary in the colour of the streak, if it can be scraped at all; also of becoming strongly magnetic when heated by the blow-pipe upon charcoal, whereas Wood Tin scarcely becomes magnetic, but is reduced to pure Tin. Klaproth observes that this Ore contains more Tin than any other Ore of the same Metal. It is found in Cornwall at St. Denis, St. Columb, Alternon, &c. Spec. Grav. 7.29.
Analysis by Klaproth:
|Oxide of Iron||0.20|