Glass Aquarium weight?

I want to set up an African rocky lake with my 10-gallon. The only problem is, I don’t know how much weight the bottom of the tank can hold. I have it on a solid oak stand (not a lip-only, but solid) and I don’t want to crack the glass by putting in rocks that are too heavy. I’ve got 2 inches of silver sand laid down, but how many pounds of rocks can I set in my tank without the bottom cracking from the stress?