Geology of Vermont
Vermont State Rocks and the State
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. The Mt. Holly Mammoth was named the Vermont State Terrestrial Fossil in May 2014. The
Charlotte Whale was designated the State Fossil in 1993 and became the State Marine Fossil in May 2014.
Links: On-line version of the Vermont
Rock Kit, a list of minerals in Vermont reported in literature and rock and mineral industries in Vermont, including granite, marble, slate and talc.
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.
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. Also see the Slate page.
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
Rock of Ages Homepage
Slate Valley Museum Homepage
USGS Mineral Resource
Data (Interactive map)
USGS Mineral Industry
Buildings Using Vermont Stone - Quarries and Beyond web site.
Mining in Vermont
Use of Granite Waste Rock
For information and educational resources concerning
minerals we recommend you visit the Mineral