distinct beds in primitive mountains, included in rocks of serpentine with which it is closely connected, but he does not give any example.[1]
Of all the rocks allied to the serpentine formation, steatite is that, without doubt, which approaches nearest to it in chemical composition. The only analyses of these two rocks which I know, are, that of serpentine by Kirwan, and of the soap-rock of Cornwall by Klaproth, who calls it seifenstein. The coincidence of these two able chemists in the proportions of the component parts of these substances, renders the idea I had formed, relative to their common origin, more probable I subjoin a comparative statement of the results of these two analyses. It is possible, that hereafter, when such experiments are multiplied, we may discover too many anomalies to allow us longer to consider these two rocks as nearly allied to each other; and that we shall be obliged to arrange soap-rock as a distinct species of steatite.
| Serpentine analysed by Kirwan. | Soap-rock analysed by Klaproth. | ||
| Silica | 0,45 | 0,48 | |
| Magnesia | 0,23 | 0,20.50 | |
| Alumina | 0,18 | 0,14 | |
| Iron | 0,03 | 0,01 | |
| Water | 0,12 | 0,15.50 | |
| ────── | ────── | ||
| 101 | 99 | ||
We see that with the exception of the silica and the water, which are most abundant in the soap-rock, there is in this last substance a diminution of about 0,03, or 0,04 of all the other component parts
- ↑ Brochant, Traité de Minéralogie, tome i. p. 471.
