Turquoise
Turquoise (callais), mineral, hydrous phosphoric alumina with some iron and copper, found sprinkled into dense, fine crystalline areas, as well as in seam fillings or veins, kidney-shaped and stalactite, blue or green, opaque, faintly glossy, hardness 6, specific weight 2, 6 to 2.8. The oriental turquoise (mineral turquoise, turquoise of the old stone), of a beautiful sky-blue colour and prized as a gemstone, comes from a trachyte breccia at Nishapur and Mashhad in Persia and from the porphyry of the Megara Valley in Sinai; similar varieties have recently been found in trachytic rocks in New Mexico, Arizona, and Nevada. Of lesser beauty is the turquoise from Jardonsmühl in Silesia, from Ölsnitz and Reichenbach in Saxony and from the slate quarries between Weckersdorf and Langenwolschendorf in Reuss. The so-called tooth turquoise (bone turquoise, occidental turquoise, turquoise of the new stone) is naturally or artificially coloured tooth enamel or ivory, in the former case of Mastodon and Deinotherium. It nearly reaches the hardness of mineral turquoise, but is usually more intensely coloured and appears bluish-grey by candlelight. Natural tooth turquoises are found in Siberia and the Languedoc. Imitations have also been produced by vigorous pressing of coloured phosphate of clay.
The colour turquoise corresponds to cyan.
Single Pigment Colours
A small overview of turquoise (PB or PG) single pigment colours suitable for miniatures, models, and dioramas.
- Cyan
- Phthaloturquoise (PB 16, transparent), PRIMAcryl 13.455
- Cobalt Turquoise (PG 50, semi-opaque), PRIMAcryl 13.456
- Turquoise Green, BLOCKX Artist Oils 663
Mixed Pigment Colours
- Turquoise Green, Amsterdam Acryl 661
- Turquoise, Plaka 36
Source: Meyers Großes Konversations-Lexikon, 6. Auflage 1905–1909