Monthly Archives: May 2014

Thomsonite from Lake Superior

Beautiful eyes usually dominate high quality Thomsonite.

Beautiful eyes usually dominate high quality Thomsonite.

Thomsonite is rare and beautiful. The most striking Thomsonite colors and patterns come from Lake Superior’s north shore in the Grand Marais area. This eyed Zeolite has to be the most attractive stone in the Zeolite family. High quality Thomsonite, with dramatic greens and pinks, is highly prized by rockhounds.

I love finding Thomsonite and polishing them to expose the gorgeous eyes.

I love finding Thomsonite and polishing them to expose the gorgeous eyes.

In this post I decided to show you before and after photos showing the Thomsonite cabochons and the pendants I made from them.

All the beachfront in the Grand Marais is private property and the owners are very protective. Some basalts in the area have Thomsonite inclusions. Extracting these gemstones involves cutting them out. The gemstone is very brittle and fragile, so hammers and chisels cannot be used.

The best deposit near Thomsonite Beach was buried years ago to create a public park. The best chance to obtain high quality Thomsonite is from old collections or local hunters that know where to find this elusive gemstone.

Thomsonite is sometimes found on Isle Royale and in the Keweenaw Peninsula of Michigan. In the Keweenaw we also find a mineral that often mimics Thomsonite. This is the colorful Prehnite. Prehnite is referred to locally as “U.P. Thomsonite” and often sports eyes and chatoyant, feathery patterns, like Thomsonite, except it is not a Zeolite. Many inexperienced rockhounds mistake Prenite for Thomsonite. Thomsonite is much less common than Prehnite.

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Recently I obtained several beautiful pieces from a dealer that had purchased an old collection of Thomsonite from an estate. These gemstones are some of the best pieces of Thomsonite I’ve ever seen. Two or three of these are spoken for and the rest will be posted on this website. I really enjoyed working with all these and hope you enjoy the pendants made from these gemstones!

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Maw Sit Sit

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Maw sit sit is rare and isn’t easy to find, primarily because it is currently found only in that single location of Burma (Myanmar). Because it is so rare, it is a popular gem among collectors but is not available through most jewelers. I stumbled across a dealer in Tucson that had some slabs of this gemstone, so I brought some home. There really was not a lot of Maw Sit Sit around. Historically, Burma (Myanmar) has been prone to embargo situations off and on for various political reasons over the years. This makes exported Gemstones from this area scarce.

Maw-sit-sit is considered to be a rock rather than a mineral, since it is composed of a number of different minerals, including kosmochlor (a mineral related to jadeite) and varying amounts of jadeite and albite Feldspar. It is often classified as a member of the jade family but it is not really a variety of jadeite. Sometimes maw-sit-sit is called a “cousin” of jade, which seems appropriate.

The only location where Maw Sit Sit is found in the world are the towns of Hpakan and Tawmaw. These towns are in the main jade mining regions in North-Western Myanmar.

The photo is of a Mother’s Day gift Bonnie now owns. I expect to make a couple more pieces in the near future.