Garnet was designated the official state mineral of Connecticutt in 1977. Some of the finest almandine garnet in the world is found in Connecticut. Garnet varies in color from pale to dark tints, including the deep violet-red of the almandine garnet. Garnet is a hard mineral also used as an abrasive in grinding wheels, saws, and sandpaper - this mineral played an important role in the history of Connecticut industry.

Garnet crystal photo by USGS - featured in the "Minerals and Materials Photo Gallery" of the U.S House Subcommittee on Energy and Natural Resources website (as a work of the U.S. federal government, the image is in the public domain). Wikipedia.org

Source:

The State Mineral - Almandine Garnet: CT.gov
Garnet - Industrial: Mineral Information Institute

Links:

State of Connecticut Symbols: Connecticut official website
Geological Symbols - 50 States List