Official State Rocks

Twenty-six of the 50 states have designated an official state stone or state rock. (Massachusetts declared one of each, and Vermont named three.) Exactly what is meant by "rock" or "stone" may be a puzzlement to the geologist, but rather than figure it out in each case I will simply list them here, each rock/stone's name linked to a photo in my gallery of state rocks and stones. The "source" link goes to the best existing material from the respective state government. My favorite site for all state symbols is at netstate.com.

Alabama: Marble (source)
Arkansas: Bauxite (source)
California: Serpentine (serpentinite) (source)
Colorado: Marble (source)
Florida: Agatized coral (source)
Indiana: Limestone (source)
Iowa: Geode (source)
Kentucky: Agate (source)
Massachusetts: Roxbury Puddingstone conglomerate (source) and Granite (source)
Michigan: Petoskey stone (Hexagonaria pericarnata, a Devonian coral) (source)
Missouri: Mozarkite (chert) (source)
Mississippi: Petrified wood (source)
Nebraska: Agate (source)
Nevada: Sandstone (source)
New Hampshire: Granite (source)
North Carolina: Granite (source)
Oklahoma: Barite roses (source)
Oregon: Thunderegg (source)
Rhode Island: Cumberlandite (source)
South Carolina: Blue granite (source)
Tennessee: Limestone (source)
Texas: Petrified palmwood (Palmoxylon) (source)
Utah: Coal (source)
Vermont: Marble, granite and slate (source)
West Virginia: Coal (source)
Wisconsin: Red granite (source)