Mariposa County has a rich history of mining operations with over 1,300 gold mines. Check out this article for some of the area’s mining history: https://westernmininghistory.com/library/23/page1/
This slab is an example of a stone named for our locale!
In addition to mariposite, gold can still be found in “them thar hills” and streams. (Always check with the landowner before collecting and observe all mining etiquette.) We also find quartz, garnets, chiastolites, and soapstone, along with other minerals, in the area.