The two large peninsulas that form the state of Michigan border the Great Lakes between the northern United States and Canada. Along the beaches of these majestic lakes, novices and expert gem seekers can find a variety of gemstones to take home as keepsakes or to turn into jewelry. The mineral-rich area and lava-rock soil provide an abundance of gem-hunting opportunities.
Chlorastrolite is Michigan’s state gem. Mainly found along the beaches of the Great Lakes and common in Isle Royale National Park, these stones are usually pebble-sized and bluish-green in color with a star pattern of crystals that resemble a turtle’s shell. Also called greenstone, this stone is a variety of the mineral pumpellyite. Chlorastrolite pebbles often contain other minerals that give them color variations, such as the pinkish hues of thomsonite.
Agate is a variety of quartz gem that gem seekers can find on almost any beach in Michigan, but primarily along the shores of lake Superior in the Upper Peninsula. They vary in color but their defining feature is their concentric banding. Due to its mystical history and the ancient belief that the stone has curing powers, jewelry makers often form agates into caps for rings or beads for necklaces and bracelets. Among the purported properties of agates are the ability to cure insomnia and skin diseases.
Hematite is an iron ore that is black or rusty reddish black in its raw form but often a shiny black in its polished gemstone form. Seekers can find the stones in old mining dumps in Michigan, and they also can be found along the shores of Lake Superior. Many local collectors may appreciate them, but most of the stones found in Michigan are unsuitable for polishing.
Jaspilite is a banded iron formation also known as banded ironstone. It occurs in the knolls between the cities of Negaunee and Ishpeming in the Upper Peninsula, predominantly on a hill called Jasper Hill. Jaspilite stones, consisting of alternating bands of light red jasper and hematite, represent some of the oldest rock formations in existence. They were created when banded layers of iron were common in Earth’s crust, about 3,700 million years ago.
References and ResourcesState Symbols USA: Michigan State Gem
Gitchee Gumee Agate and History Museum, Grand Marais, Michigan: Agate Basics
Central Michigan University: Hematite
Amethyst Galleries Mineral Gallery: The Mineral Hematite