In the English translation of Solinus's _De Mirabilibus_ (_The excellent and pleasant worke of Julius Solinus containing the noble actions of humaine creatures, the secretes and providence of nature, the descriptions of countries ... tr. by A. Golding, gent._, Lond., 1587), chapter xv. on Arabia has the following:
"Hee findeth likewise the Iris in the Red sea, sixe cornered as the Crystall: which beeing touched with the Sunnebeames, casteth out of him a bryght reflexion of the ayre like the Raynebowe."
Iris is also mentioned by Albertus Magnus (_De mineralibus_, Venet., 1542, p. 189), by Marbodeus Gallus (_De lapidibus_, Par. 1531, p. 78), who describes it as "crystallo simulem sexangulam," by Lomatius (_Artes of curious Paintinge_, Haydocke's translation, Lond., 1598, p. 157), who says, "... the Sunne, which casting his beames vpon the _stone Iris_, causeth the _raine-bowe_ to appeare therein ...," and by "Sir" John Hill (_A General Natural History_, Lond., 1748, p. 179).
Figures of the Iris given by Aldrovandi in the _Musæum Metallicum_ clearly depict crystals of quartz.
[120] PAGE 48, LINE 16. Page 48, line 18. _Vincentina, & Bristolla (Anglica gemma siue fluor)_. This is doubtless the same substance as the _Gemma Vincentij rupis_ mentioned on p. 54, line 16 (p. 54, line 18, of English Version), and is nothing else than the so-called "Bristol diamond," a variety of dark quartz crystallized in small brilliant crystals upon a basis of hæmatite. To the work by Dr. Thomas Venner (Lond., 1650), entitled _Via Recta_ or the _Bathes of Bathe_, there is added an appendix, _A Censure concerning the water of Saint Vincents Rocks neer Bristol (Urbs pulchra et Emporium celebre)_, in which, at p. 376, occurs this passage: "This Water of Saint _Vincents_ Rock is of a very pure, cleare, crystalline substance, answering to those crystalline Diamonds and transparent stones that are plentifully found in those Clifts."
In the _Fossils Arranged_ of "Sir" John Hill (Lond., 1771), p. 123, is the following entry: "Black crystal. Small very hard heavy glossy. Perfectly black, opake. Bristol (grottos, glass)" referring to its use.
The name _Vincentina_ is not known as occurring in any mineralogical book. Prof. H. A. Miers, F.R.S., writes concerning the passage: "_Anglica gemma sive fluor_ seems to be a synonym for _Bristolla_, or possibly for _Vincentina et Bristolla_. Both quartz and fluor are found at Clifton. In that case Vincentina and Bristolla refer to these two minerals, and if so one would expect Bristolla to be the Bristol Diamond, and Vincentina to be the comparatively rare Fluor spar from that locality."