Each state has their own designated Gem stone. Find your state or state of interest to identify your stone.
Note that not all of the 50 states have assigned themselves an official gemstone, but most of them have decades ago.
Here is a list of state official gemstones:
Alabama - Star Blue Quartz
Alaska - Nephrite Jade
Arizona - Turquoise
Arkansas - Diamond
California - Benitoite
Colorado - Aquamarine
Florida - Moonstone
Georgia - Quartz
Hawaii - Black Coral
Idaho - Star Garnet
Kentucky - Freshwater Pearl
Louisiana - Crassostrea Virginia Eastern Oyster Shell
Maryland - Patuxent River Stone
Massachusetts - Rhodonite
Michigan - Chlorostrolite
Minnesota - Lake Superior Agate
Montana - Sapphire
Nebraska - Blue Agate
Nevada - Black Fire Opal
New Hampshire - Smoky Quartz
New Mexico - Turquoise
New York - Garnet
North Carolina - Emerald
Ohio - Ohio Flint
Oregon - Oregon Sunstone Labradorite
South Carolina - Amethyst
South Dakota - Fairburn Agate
Tennessee - Tennessee River Pearl
Texas - Texas Blue Topaz
Utah - Topaz
Vermont - Grossular Garnet
Washington - Petrified Wood
West Virginia - Mississippian Lithostrotionella Fossil Coral
Wyoming - Wyoming Nephrite Jade
Source:
https://www.gemcoach.com/state-gemstones/?fbclid=IwAR1qm_WzzXImm0w2UohamzvPoqekoZAw_uP4nNgNKG6OIHhKqwgRK6hxOrM