Note 15 — BOOK XII.

Agricola (De Natura Fossilium, p. 215) in discussing substances which originate from copper, gives among them green chrysocolla (as distinguished from borax, etc., see Note 8 above), and says: "Native chrysocolla originates in veins and veinlets, and is found mostly by itself like sand, or adhering to metallic substances, and when scraped off from this appears similar to its own sand. Occasionally it is so thin that very little can be scraped off. Or else it occurs in waters which, as I have said, wash these minerals, and afterward it settles as a powder. At Neusohl in the Carpathians, green water flowing from an ancient tunnel wears away this chrysocolla with it. The water is collected in thirty large reservoirs, where it deposits the chrysocolla as a sediment, which they collect every year and sell,"—as a pigment. This description of its occurrence would apply equally well to modern chrysocolla or to malachite. The solution from copper ores would deposit some sort of green incrustation, of carbonates mostly.