On a resent trip to central Cal. Coast, my boys and I spent some time at Moonstone beach in Cambria. It's a nice spot where a stream comes down from the coastal mountains to the coast. This place has the most varied deposits of pebbles on the beach, many polished to a nice sheen.
I even found a nice moonstone.
Also a couple of what at first seemed to be sea glass, but on a closer look may have washed down from the mountains.
Zoom in to see some of the variety to be found there. Looks like the is some geology going on in those hills