Monthly Archives: May 2010

Sharply terminated orange kyanite crystal

One remarkable discovery that surfaced for the first time ever at Tucson 2010 was the fine mineral specimens of orange kyanite. The kyanite is an eye-catching translucent orange to red-orange color. Only about 5% of the ones we saw were actually terminated – a rarity with kyanite crystals.  There were also a handful twinned ones, but they weren’t as attractive as the top terminated crystals.   Orange kyanite is only found in Nani, Loliando, Arusha Region, Tanzania.  This is a close neighbor of the Loliando garnet diggings, which has recently been in the spotlight for its spectacular, world-class red-orange spessartine garnet crystals. Only about 5% of the orange kyanite crystals we saw were terminated, and we picked out only the best of these, focusing especially on those showing twinning.

Unusual twinned termination

Kyanite is a polymorph with two other minerals; andalusite and sillimanite. A polymorph is a mineral that shares the same chemistry but a different crystal structure with another, or other, minerals. Kyanite is an attractive mineral that has a near sapphire like blue color in some especially nice specimens. Kyanite has a unique characteristic in that it has a wide variation in hardness, in the same crystal. The hardness of kyanite is approximately 4.5 when scratched parallel to the long axis of the crystal and approximately 6.5 when scratched perpendicular to or across the long axis. Other minerals usually have variable hardness on different crystal faces due to a different concentration and orientation of the atoms in the structure.

The orange color reportedly comes from the chromophores manganese, which is incorporated in trace amounts in the molecular lattice of the crystal.

A large, 1.8" crystal

Orange kyanite was first discovered in Loliondo, Tanzania, in 2005.  Unfortunately, it was very soft and crumbled to dust, so no specimens from this find made it to the crystal dealers.  In late 2008, more solid crystals were found, but they were typically thin, slender crystals.  Finally in fall 2009, the diggers discovered a layer with solid, fat, sharp orange crystals; some, reportedly found in pockets, are terminated. Many of the crystals have bits of attached mica or quartz.  On most crystals, the edges appear ragged and irregular. Technically this is not damage – it is just how they grew in contact with the surrounding schist matrix.

Lovely translucent red-orange color

We’ve been selling specimens from this find almost as fast as we can list them.  Here’s a link to the Kyanite gallery on our website, where we may have some available.  If there are none shown there, you can contact us regarding availability through the About Us button on our website, www.treasuremountainmining.com.

Orange used for jewelry and is especially popular with those interested in metaphysical crystals and crystal healing.