FMF - Friends of Minerals Forum, discussion and message board

[Ken]

These stones all have a hardness of about 3.5 so I think they are serpentine. That last stone has a very odd shape, took me a while to figure it out. I've read that the magnetism is caused by magnetite but I can't see anything black in these stones so could it be hematite?

[alfredo]

Riverside county has lots of metamorphic rocks with magnetite in them. I've seen many in the San Gorgonio Pass - Palm Springs area. The soft part might be mica or chlorite rather than serpentine. Usually if a dark rock is magnetic, the reason is magnetite inclusions - Other magnetic minerals are possible too but much less common.

[Ken]

You're right about there being a lot of magnetite in that area, I do recall seeing a good deal of it around there. Thanx for the reply.