It''s a pretty big stone. Are you getting white gold or platinum/palladium? If it''s white gold it will wear down and have to re-tipped eventually. Platinum and Palladium will not really wear down but it could still deform if struck by a hard object, same is true with white gold. To be honest regardless of the metal for peace of mind, I''d definitely get 6 prongs. Most 3+ ct rounds I''ve seen are mounted in 6 prongs. I had a customer who bought a 2.52 carat round VS2/F several years back, and I really recommended to him at the time to get 6 prongs (it was a platinum mounting)... he just called me up a few weeks ago and told me they went scuba diving while on vacation, she was wearing her bridal set and there was a current in the water or something and she was pushed into some rocks. Luckily she escaped real injury except a few scrapes and bruises, but her ring was badly mangled. 2 of the prongs had deformed, but the stone was still held in place by the other 4 even though very crooked. The whole ring basically was destroyed, we ended up scrapping it, I gave him credit for the scrap and we made a new one. But luckily he didn''t lose that stone. Anyhow I don''t mean to scare you, these things don''t happen every day and not everyone is hard on their jewelry. You just never know.