Note 2772 — BOOK XXXVI. THE NATURAL HISTORY OF STONES. (continued 2)

This is more likely to apply to a white marble than to a calcareous or gypseous spar. Suetonius says, c. 14, that Domitian, when he suspected that plots were forming against him, caused the porticos in which he walked to be lined with Phengites, which by its reflection showed what was going on behind his back.