[Ray76]

Tidbit

There are old gold and quartz mines nearby.

Location marked on this map

http://mapper.acme.com/?ll=39.54708,-121.50694&z=14&t=T&marker0=39.55151%2C-121.51857%2C3.2%20km%20WxNW%20of%20Oroville%20Dam%20CA&marker1=39.54582%2C-121.52058%2C3.2%20km%20WxNW%20of%20Oroville%20Dam%20CA

info:

https://mrdata.usgs.gov/mrds/show-mrds.php?dep_id=10109115

info about mine shafts, etc

https://books.google.com/books?id=_XHOAAAAMAAJ&pg=PA153&lpg=PA153&dq=south+banner+mine+%22journal+of+mines+and+geology%22&source=bl&ots=WDiLQUEMmV&sig=RxC1nl-3CkY2KcpE9OzttqmYmBE&hl=en&sa=X&ved=0ahUKEwiRs5uMjZ3SAhUJSiYKHSk_BHIQ6AEIPjAH#v=onepage&q=south%20banner%20mine%20%22journal%20of%20mines%20and%20geology%22&f=false

https://books.google.com/books?id=v3LOAAAAMAAJ&pg=RA1-PA82&lpg=RA1-PA82&dq=banner+mine+oroville&source=bl&ots=kJDV_aiNdg&sig=p3by03Y_ab_YYImYtf-vIWIwYcU&hl=en&sa=X&ved=0ahUKEwjgpdTMgZ3SAhUGbSYKHetKB9YQ6AEIUTAN#v=onepage&q=banner%20mine%20oroville&f=false

[mad_as_he$$]

I have seen similar rock all over gold country in both Kalifornia and Nevada. I always collect samples for testing for gold. It breaks easily with a hammer and I grind it in old kitchen blenders.