I didn't know sodalite was tenebrescent - able to change color when exposed to uv light. This property is reversible unless the stone is subjected to high heat (reference 1 below).  

I stumbled upon various videos of rockhounds looking for such stones on Lake Superior beaches in Michigan's Upper Peninsula.  One such video covered the discovery of yooperlite in 2017 by Erik Mintamaki.  

Technically these rocks are “syenite clasts containing fluorescent sodalite” but his trademarked name yooperlite is much easier to say! Note : He is not the first to find these rocks but he was the first to have a scientist confirm the presence of sodalite in the area in 2018. 

Erik now takes groups out prospecting! Finders keepers. He also shared this Yooperlite Hunting 101 video which gives tips on where and how to search.  Yooperlites are not unique to Michigan nor Lake Superior. You can find them on several Great Lake beaches. By extension, the Canadian provinces which also share the Great Lakes would be good hunting grounds. The whole area is mineral rich. 

But as he points out in the video, be sure to check if it is permissible to remove rocks from the particular beach you want to hunt on. It's not allowed in National Parks, for example.

Check out more information on the Yooperlites Facebook page.

AtomicExcitation sells Great Lakes fluorescent sodalite as well as wire wrapped pendants such as this one.  Shown in daylight :

And under UV light :

Some of the best fluorescent sodalite comes from Greenland. Like hackmanite which is a sulfur rich form of sodalite. This carved hackmanite dark green sodalite specimen shown below is available from Canadian supplier, Gotstonedjewelry

Hackmanite was first discovered in Greenland way back in 1896 and named after a Finnish geologist. In 1991, the first gem quality hackamite deposit was discovered in Quebec, Canada. 

The most desirable tenebrescent sodalite comes from Myanmar and Afghanistan,. There are colorless ones which change to a light color and even a deep purple. This rare faceted Myanmar hackmanite gem from clearwatergemsuk. It glows pink and orange under uv light. "After exposure to ultraviolet light for 10-30 seconds the gem also emits a phosphorescent glow in total darkness - it glows in the dark!"

Note : We often get the blue sodalite form for jewelry making. Do not confuse blue (in daylight) sodalite from lapis lazuli. Blue soldalite has white veining. Lapis lazuli might have sodalite in it but what characterizes lapis lazuli is the presence of pyrite (fool's gold). There is no pyrite in sodalite. 

Well known sources of blue sodalite are : Litchfield, Maine; Magnet Cove, Arkansas; northern Namibia; Golden, British Columbia; Bancroft, Ontario; Kola Peninsula of Russia; and the Ilimaussaq area of Greenland.


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Original Post by THE BEADING GEM