Bixbite

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Bixbite
Image:Bixbite.gif
General
Category	Mineral (cyclosilicate)
Chemical formula	Be₃(Al Mn)₂Si₆O₁₈
Identification
Color	Orange-red to red to purple-red
Crystal habit	Elongate or tabular first order prisms.
Crystal system	Hexagonal
Cleavage	Basal, seldom visible
Fracture	Conchoidal
Mohs Scale hardness	7.5 - 8.0
Luster	Vitreous
Refractive index	1.567-1.580
Pleochroism	Purple-red/orange-red to red
Streak	White
Specific gravity	2.66-2.70

Bixbite (also known as red beryl, red emerald, or scarlet emerald) is a red variety of beryl (emerald), Be₃(Al,Mn)₂(SiO₃)₆. It was named after the Utah mineral collector Maynard Bixby, who first discovered it at Topaz Cove in the Thomas Range of Juab County, Utah ^[1]. Bixbite should not be confused with the similarly named bixbyite. Bixbite is rare and has only been reported from a handful of locations including:

Wah Wah mountains, Beaver County, Utah
Paramount Canyon, Sierra County, New Mexico
Round Mountain, Sierra County, New Mexico
Thomas Range, Juab County, Utah

The greatest concentration of gem-grade red beryl comes from the Violet Claim in the Wah Wah mountains of mid-western Utah, discovered in 1958 by Lamar Hodges, of Fillmore, Utah, while he was prospecting for Uranium ^[2].

While gem beryls are ordinarily found in pegmatites and certain metamorphic rocks, Bixbite occurs in topaz-bearing rhyolites. It formed by crystallizing under low pressure and high temperature from a pneumatolitic phase along fractures or within near-surface miarolitic cavities of rhyolitic magmas. Associated minerals include bixbyite, quartz, orthoclase, topaz, spessartine garnet, pseudobrookite and hematite. The red color is thought to be from manganese substituting for aluminium in the beryl structure.

Gem-quality bixbite is very rare, and the largest faceted gemstones are less than three carats (600 mg) in size.