101 - Ruby and Zoisite

ID	101
Mineral	Ruby Zoisite
Location	Longido - Arusha - Tanzania
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Ruby information at mindat.org View Zoisite information at mindat.org

ID	3473
Long ID	1:1:3473:5
IMA Status	0 1
Variety of	1136
Entry type	2
Description	A red, gem variety of corundum. The red colour is caused by minor amounts of trivalent Cr replacing Al in the crystal structure. In traditional gemmological terms, ruby has to be blood-red and of clear, facetable quality to justify the name, however...
Colour	Red
Hardness (min)	9.0
Hardness (max)	9.0
Crystal System	Trigonal
UV	The intensity of fluorescence is a function of Cr concentration and the Cr/Fe ratio, because the presence of Fe or an excess of Cr tends to eliminate or quench the fluorescence in ruby.

ID	4430
Long ID	1:1:4430:7
Formula	`Ca₂Al₃[Si₂O₇][SiO₄]O(OH)`
IMA Status	0 1
Occurrence	Pegmatite in eclogite
Other Occurrences	Medium grade regionally metamorphosed rocks, eclogites, blueschist facies metamorphic rocks.
Discovery Year	1805
Diapheny	Transparent,Translucent
Cleavage	Perfect on {010} Imperfect on {100}
Tenacity	brittle
Colour	Colourless, purple, greyish-white, grey, yellowish-brown, yellow, pink, green, blue, violet
Hardness (min)	6.0
Hardness (max)	7.0
Lustre	Vitreous, Pearly
About the name	Originally named saualpite for the locality Saualpe in Carinthia, Austria, where it occurs in eclogites. The name zoisite was introduced by A.G. Werner in 1805 to honour Sigmund Zois, Baron von Edelstein (1747-1819), Austrian scholar who financed mineral-collecting expeditions. It was from Baron Zois that Werner obtained the holotype specimen from Saualpe (found by mineral dealer Simon Prešern in 1804).
Streak	White
Crystal System	Orthorhombic
Cleavage Type	Perfect
Fracture type	Irregular/Uneven,Conchoidal
Morphology	Prismatic crystals, columnar to compact, massive
Comment Luster	Pearly on cleavage {010}
shortcode_ima	Zo

Ruby and Zoisite