Geology and Mineral Resources

Geology of Vermont

Vermont State Rocks and the State Mineral

Vermont has a number of rock and mineral based industries that are important both historically and economically.

We have three State Rocks-granite, marble and slate.

Vermont's State Mineral is talc, the State Gem is garnet, and the State Fossil is the Charlotte Whale.

Click here for an on-line version of the Vermont Rock Kit.

Talc and calcite, Ludlow, VT.
Talc, our State Mineral, is very soft, pale green mineral used in talcum powder. It is also used to coat products which need to slide apart easily, such as nested stacks of plastic pails in a hardware store! Soapstone, composed of chlorite and talc, can withstand intense heat and is used by some companies to make countertops and sinks. The Green Mountains are comprised of folded and faulted metasedimentary rocks, metamorphosed volcanic rocks and slivers of ocean crust (serpentinized ultramafic rocks). Talc, soapstone, and verde antique are associated with the ultramafic rocks. Talc is currently mined in the Ludlow area.

Marble blocks ready to ship, Danby, VT.

Marble, Danby, VT.

Marble, a metamorphic rock composed principally of calcite, is found in western Vermont. The marble in Vermont was formed by the metamorphism of Cambrian to Ordovician age limestones. Marble from Vermont's Danby quarry has been used in famous buildings such as the Thomas Jefferson Memorial in Washington, D.C., the United Nations Building in New York, and the Chiang Kai-Shek Memorial in Taiwan. Most marble currently quarried in the state is crushed and used as filler in paint, paper and plastic.

Green Slate, Poultney-Fair Haven area, VT.

Slate, also a metamorphic rock, is quarried in southwestern Vermont. Slate is a very fine-grained rock composed mainly of quartz and mica. Vermont slates formed about 475 million years ago during the Taconic Orogeny, a period of mountain building. When sedimentary rocks, such as shales or siltstones are metamorphosed, they become slate. Vermont slates are generally black, green, purple or mottled, depending on the amounts of chlorite (green) and iron (red to purple) they contain. Slate is on the roof of the Vermont State House. Slate is used for flooring and as crushed product.

Granite quarry, Barre, VT.

Granite, Barre, VT.

Granite, an igneous rock, occurs as small to large plutons in eastern Vermont. Most granite in Vermont is part of the New Hampshire Plutonic Series and is Devonian in age, making it quite a bit younger than the slates and marble of western Vermont. The granite from Barre is world famous for its use as monument stone.

For more information on rocks in Vermont we recommend you visit:

Rock of Ages Homepage
Slate Valley Museum Homepage
USGS Mineral Resource Data (Interactive map)
USGS Mineral Industry Survey Site.

For information and educational resources concerning minerals we recommend you visit the Mineral Information Institute.