Holy Cow. I typed a large reply only to have it disappear.
I'll try again>
No it is closed. The BLM gifted our public lands to the state park system some time ago and since then collecting in the park is not allowed. This included the famous Buried Forest and Hidden Forest wood locations with some of the best preserved Petrified wood in CA. I have known people who have ignored the rules and collected and been caught and although I am not aware of anyone being fined or ticketed they were made to dump what they collected. The Opal mines (Nowak and Barnett) were open for a time and I believe the Nowak is still a patented mine but privately owned by a group of about 15 people. The Barnett Mine after Dick Barnett passed away and his boys didn't keep the mine reverted to State hands and closed. I used to take Cub Scouts up there every year and collect. One year the ranger lady came by and asked what all the scouts had come to red rock for and I told her we were collecting opals the next day. She said we couldn't do that "We can't have people taking buckets of material or there would be nothing left for people" I told her the scouts, if they weren't too bust throwing rocks at each other would be taking their finds home in film canisters. She said oh thats okay then. She stopped by the next night to see how we did and I showed her my little finds and what she said made me bite my tongue. "Really, I took home a couple buckets and I didn't find a thing" always funny when rules don't apply to them because they think oh there is only a couple of us so what damage can we do? Next year we met ranger rick who read the boys the riot act and said they couldn't disturb the surface or use any type of tools hammers or picks but if they see an opal on the ground they could pick it up. I never took the scouts back again.
You can collect just North of the park in the hills just outside the North Boundary and the material there is Palm Wood, Palm Root and very colorful agates. Take Redrock Inyokern rd till it hits Last Chance Canyon rd back to just before it starts down into the canyon. You will have a side rd intersect it from the West at that point and the hills have just started around you. You are outside the park and free to collect and material is good if you hike and pay attention.