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February 10, 2018 Weekly Geology Guest, Kyanite

February 10, 2018
Greetings from the Bluff Park Back Porch, way up yonder on Shades Mountain (1,109′) in Alabama:

Admin:  Let me know if you wish to continue to be on this email distribution list.  After 1-month, if I don’t hear from you, I will remove you.  Thanks, Randall Week 4
This week’s industrial minerals are Kyanite / Sillimanite / Andalusite.

Kyanite is a typically blue silicate mineral, commonly found in aluminium-rich metamorphic pegmatites and/or sedimentary rock. Kyanite in metamorphic rocks generally indicates pressures higher than four kilobars.

USESKyanite is used primarily in refractory and ceramic products, including porcelain plumbing and dishware. It is also used in electronics, electrical insulators and abrasives.
Kyanite is one of the index minerals that are used to estimate the temperature, depth, and pressure at which a rock undergoes metamorphism.
Kyanite crystals (7cm long)
Kyanite crystals.jpg
User:AelwynSelf made picture


Deep blue kyanite


Sillimanite is an aluminosilicatemineral with the chemical formula Al2SiO5.
Natural sillimanite rocks cut into the required shape and size are used mainly in glass industries. Sillimanite is the best raw material for the manufacture of high alumina refractories or 55-60% alumina bricks.
Sillimanite Locality: Orissa, India (Locality at Size: thumbnail, 2.7 x 2.1 x 0.9 cm Sillimanite (huge gem xl)
Rob Lavinsky, – CC-BY-SA-3.0

Andalusite is an aluminiumnesosilicatemineral with the chemical formula Al2SiO5.
Andalusite is an aluminium compound with high heat resistance used in furnaces, kilns and other industrial processes.
Andalusite Locality : Lüsens valley, Sellrain valley, North Tyrol, Tyrol, Austria Size : 7.4×6.2cm
Didier DescouensOwn work


Editors Note:  It is the intent of this site to keep this discussion as simple as possible, so as to educate the interested general public and not to discuss with the geology crowd the latest geologic theories and nuances.  Thanks, R
“No copyright infringement intended.
The rights belong to their respective owners”



We will now continue down the Industrial Mineral dusty trail and continue with limestone and dolomite.
Enjoy the adventure!

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