I dont think theres an official gemstone for the US but there is a Official gemstone for each state.
Turquoise is the official state gemstone of Arizona.
The Freshwater Pearl is the official state gemstone of Kentucky.
Turquoise is the official gemstone of Nevada.
Ammolite is the official gemstone of Alberta, Canada.
The Netherlands doesn't have an official national gemstone. Turquoise is the national gemstone of Iran, opal is the national gemstone of Australia and amber is the national gemstone of Spain.
Pennsylvania has no official rock, stone, gemstone or mineral.
Jamaica has an official bird, tree, flower, fruit, and... costume, yet no official gemstone. For many things the country is well known, but minerals are not one of them.
Almandine garnet.
The Garnet is the official gemstone.
There is no official gemstone for Virginia.
The official state gemstone of Alabama is the Star Blue Quartz, adopted in 1990.
Virginia has no official rock or gemstone.