Whoever built it had access to big chunks of waste glass as well as a variety of rocks from near and far. One of those, the green one in the lower right, is a fine specimen of actinolite schist:
To my knowledge, you won’t find such a thing in Oakland. I got my first hand specimen of actinolite from that rock shop on 101 next to Squaw Rock on the Russian River, south of Hopland. I asked the owner, as I often do, “What do you have that’s local?” and he handed me that one. The boulder in this driveway looks just the same.