How do you identify chlorastrolite?
Chlorastrolite is found chiefly as small rounded pebbles on the beaches of Isle Royale in Lake Superior and also throughout the Keweenaw Peninsula associated with the native copper deposits. The Keweenaw nuggets are found as black to green colored nodules in vesicles of the amygdaloid basalts.
What is chlorastrolite made of?
CHLORASTROLITE, (Compact, massive variety of pumpellyite — Ca2(Mg,Fe)Al2(SiO4) (Si2O7)(OH)2·H2O ). DESCRIPTION: As noted above, chlorastrolite is a variety of the mineral pumpellyite.
Where is chlorastrolite found?
Chlorastrolite occurs as amygdaloid structures and fracture fillings in basalt, and when the water and wave action has worn away the basalt, they are found as beach pebbles and granules in loose sediments. It is found in the Keweenaw Peninsula of the Upper Peninsula of Michigan and Isle Royale in Lake Superior.
How much is Isle Royale greenstone worth?
The gem-setter estimates the value of Isle Royale Greenstone at about $40,000 a pound. That puts this Lake Superior gem well ahead of the better known agate, with a current value of about $200 a pound.
Where can I find Chlorastrolite in Michigan?
Keweenaw Peninsula
Chlorastrolite is also known as the Isle Royale greenstone because it is ONLY found on the Isle Royale and the Keweenaw Peninsula of Michigan.
Are there emeralds in Michigan?
There are emeralds in Michigan. Even though the colors of these emeralds are usually light they can still come in dark green to dark blue green. Theses emeralds are found in an old iron mine in Marquette County.
Where can I find chlorastrolite in Michigan?
What is chlorastrolite used for?
Naturally, gem-quality chlorastrolite specimens are often used in jewelry. When polished, the mineral becomes a beguiling green-blue color laced with a web of turtle-shell style markings vaguely reminiscent of Petoskey stones. The mineral’s unique patterning inspired its name, which means “green star stone.”
Where can I get Chlorastrolite in Michigan?
What is Chlorastrolite used for?
What is the most valuable mineral in Michigan?
Its occurrence in that region is what gives this mineral its arguably prettier common name: Isle Royale Greenstone. The state legislature named chlorastrolite Michigan’s official gemstone in 1973.