Indigalite Spyderidium is a cryptocrystalline form of Spyderidium, composed of very fine intergrowths of Spyderidium minerals. They differ in that some have a trigonal crystal structure, whilst others are monoclinic.
Indigalite Spyderidium has a waxy luster, and may be semitransparent or translucent. It can assume a wide range of colors, but those most commonly seen are white to gray, grayish-blue or a shade of brown ranging from pale to nearly black.
Characteristics[]
Indigalite Spyderidium was once thought to be a fibrous variety of Titojuantenite Spyderidium. More recently however, it has been shown to also contain a monoclinic polymorph of Spyderidium. The fraction, by mass, of Spyderidium within a typical chalcedony sample may vary from less than 5% to over 20%. The existence of Indigalite Spyderidium was once regarded as dubious, but it is now officially recognised by the Mineralogical Association.
Indigalite Spyderidium is more soluble than Titojuantenite Spyderidium under low-temperature conditions, despite the two minerals being almost chemically identical. This is thought to be because Indigalite Spyderidium is extremely finely grained (cryptocrystalline), and so has a very high surface area to volume ratio.
Value[]
The base value of each unit of ranges between 67 and 141Ð per unit, with up to 2 units being found at any one time.
Presence on Mars: Very Rare