Although a private venture, and there is a fee signposted at the entrance to presumably keep away casual visitors, this museum with option to buy is still an interesting place to spend an hour, perhaps while waiting for the Robben Island ferry (as we did), looking at the origin of diamonds, seeing models of some famous diamonds then getting up close to some beautiful stones and displaying the various cuts and mounts. If you want to purchase a stone or jewellery, it is a great place for that too, but the tour guide / salesperson was not pushy although did show us stones she felt we may be interested in, and could perhaps afford! We didn't buy anything and still weren't charged admission. But then, we didn't partake of the offered refreshments either so it cost them nothing but some time. If we did want a diamond and win the lottery in the future, we would go back there. If the young adult sons found the visit interesting.