Culumbus
This beach has small black and red pebbles. Also, a huge, impressive rock offering its shadow during the hottest hours of the day.
It was -and still is- popular with nudists. It is usually fairly quiet and there are no sun beds or umbrellas. Therefore, you should bring with you any supplies you might need. At a short distance east there is the underwater crater of Culumbus which last erupted in 1650. The crater is 500 metres from the surface, but its SW end is just 10 metres down.