Note 41 — BOOK IX.[1] (continued 2)

[Pg 402][41] Aes purum sive proprius ei color insederit, sive chrysocolla vel caeruleo fuerit tinctum, et rude plumbei coloris, aut fusci, aut nigri. There are six copper minerals mentioned in this sentence, and from our study of Agricola's De Natura Fossilium we hazard the following:—Proprius ei color insederit,—"its own colour,"—probably cuprite or "ruby copper." Tinctum chrysocolla—partly the modern mineral of that name and partly malachite. Tinctum caeruleo, partly azurite and partly other blue copper minerals. Rude plumbei coloris,—"lead coloured,"—was certainly chalcocite (copper glance). We are uncertain of fusci aut nigri, but they were probably alteration products. For further discussion see note on p. 109.