Bixbite

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Bixbite
Chemical composition Be3Al2(SiO3)6 Beryllium aluminum silicate
Crystal system Hexagonal
Habit Prismatic
Cleavage Basal, poor
Fracture Conchoidal to uneven
Hardness 7.5 - 8
Optic nature Uniaxial -
Refractive index 1.561 - 1.577
Birefringence 0.004 - 0.009
Dispersion Low, 0.014
Specific gravity 2.63 - 2.72
Lustre Vitreous
Pleochroism Weak

Bixbite.jpg

Bixbite (or "red beryl") is the allochromatic orange-red to purplish-red variety of beryl which owes its color to manganese (Mn) impurities.
Physical and optical properties may be slightly higher than usual beryl properties.

Bixbite was named after Maynard Bixby of Utah, USA.
Locations where this rare mineral is found include Utah and New Mexico, USA.

Bixbite is rarely free from inclusions (most are heavily included) and stones above 3ct. are scarce.

Red (bixbite) and pink (morganite) beryls are now manufactured using the hydrothermal process by Biron International in Australia, by ANICS in Japan and by Novosibirisk in Russia. The coloring agent in these synthetics is titanium and/or cobalt, opposed to larger quantities of manganese in their natural counterparts.
The pleochroism in these synthetics is usually medium to strong whereas it would be weak in natural red beryl. The distinguishing factor for the hydrothermal synthetic red beryls is inhomogeneous growth patterns seen under magnification.