Note 6 — BOOK V.

[Pg 108][6] Rudis,—"Crude." By this expression the author really means ores very rich in any designated metal. In many cases it serves to indicate the minerals of a given metal, as distinguished from the metal itself. Our system of mineralogy obviously does not afford an acceptable equivalent. Agricola (De Nat. Foss., p. 360) says: "I find it necessary to call each genus (of the metallic minerals) by the name of its own metal, and to this I add a word which differentiates it from the pure (puro) metal, whether the latter has been mined or smelted; so I speak of rudis gold, silver, quicksilver, copper, tin, bismuth, lead, or iron. This is not because I am unaware that Varro called silver rudis which had not yet been refined and stamped, but because a word which will distinguish the one from the other is not to be found."