I've started 3 different colonies thus far including one in the middle of the freaking desert, and so far I have found almost no sand at all. Maybe one or 2 sand deposists after scouring the map. For comparison I find about 6-9 gold desposits per biome at least and no sand or 1 sand. All my productions are grinding to a halt without the ability to make glass.
Are you building any mines? All mines (no matter where you build them) output a little sand now and then.
I think people have been overly conditioned to only build on pips. Actually, dropping a mine on plain ground is really really super useful.
Just build in the desert. Sure, wood is so scarce it's more valuable than gold and there's no food to forage, but you'll never lack for sand!