Sims 2 Castaway: How do I harvest Fine Sand? I Have found Crystal Island but no Fine Sand in sight.?

I am almost done with the game, and I'm trying to build a bungalow but I need Fine Sand for glmaking. I've walked all over Crystal Island, but cannot find any prompts for harvesting the sand anywhere. I have also made all the metal tools on the forge, so I should be up to date with that. Could someone who has found the Fine Sand on Crystal Island tell me specifically where it is and how to harvest it? Thanks in advance.