Brewer's Bay is the only non-white sand beach on the island. The sand is a dark gold. The bay offers snorkeling opportunities in calm weather, but because of the runoff routes from the mountains, the water is often murky after even moderate rain.
Development around the island has circumvented nature's natural filtration systems, such as salt ponds, and as a result, most beaches are not attractive after heavy rains because of runoff from roads that zig and zag up the mountainsides, and home development sites cut harshly into the sides of the mountains as well.
That said, Brewer's Bay is an excellent place to go if you want good snorkeling right off the beach, decent food, friendly locals, reasonably warm water (late April), and some peace and quiet. Watching the pelicans diving into the watch for fish is fascinating, but can be a little unnerving when they plunge in near where you are snorkeling. These pelicans and other predators (nothing scary) are after the large schools of small "feeder fish," which will let you swim along in their midst. If you take some bread or bagels with you in a plastic bag, the smaller fish will almost eat right out of your hand.
You can take a taxi from Road Town. The drivers are happy to narrate what you are passing and will stop high above the harbor for a nice scenic photo opportunity.