Note 933 — BOOK XXXIII. THE NATURAL HISTORY OF METALS.647
John Bostock translation
As a “trigarius.” See B. xxviii. c. 72, and B. xxix. c. 5. From Suetonius, c. 18, we learn that the Emperor Caligula, also, had the Circus sanded with minium and chrysocolla. Ajasson is of opinion that the chrysocolla thus employed was a kind of yellow mica or talc.