hair stone

See also: hairstone

hair stone (countable and uncountable, plural hair stones)

(mineralogy) Clear quartz crystal containing coloured filaments caused by impurities. Particular kinds are sometimes known as Venus’s hair stone or Thetis’s hair stone.

1810, Richard Kirwan, Elements of Mineralogy‎, 3rd edition, volume 1, pages 301–302:
In some aggregates of quartz and shorl, slender capilliform needles of red shorl traverse the quartz, and cross each other in various directions. This stone is in some estimation, and is by the Germans called hairstone. It is found in Siberia.
1834, Nathaniel Fish Moore, Ancient Mineralogy or, An Inquiry Respecting Mineral Substances Mentioned By The Ancients‎, page 142:
This goldenhair might be compared, or is perhaps the same, with the Venus hairstone; which is quartz traversed by such acicular crystals of the red oxide of titanium.
1861, E.L.L, Temple Bar‎, volume 3, page 388:
“Venus's-hair stone,” rock-crystal banded with pearly filaments of amianthus; “Cupid's pencils,” a violet quartz enveloping separate little tufts of hair-like oxide of iron, of a bright golden brown; “marmot's-hair stone,” not unlike the preceding, yet with a difference, the oxide of titanium, which makes the little marmot's hairs, being disposed in long tress-like filaments, and not in tufts…

English