The Graff Hallucination is a sculptural masterpiece; a celebration of the miracle of coloured diamonds. For many years I have thought about creating a truly remarkable watch that illustrates our all-consuming passion for diamonds. The Hallucination has made my diamond dream a reality.

Unfortunately, some of the young talants are becoming fashionable. And anything that's fashionable can become unfashionable. So one has to watch that. And it's very easy today because there are so many events - art fairs, gallery openings, etcetera. In fact, that's another thing that concerns me, the quantity of gallery openings. In my office in London, I get back after a week, and I have 30 invitations. It's too much.

Your eye becomes more mature. What you don't see the first time, you keep looking, and eventually you'll see it. And when you are confident with what your eye sees, you know you've got to have it.

Collecting contemporary art I started with some of the younger artists. Although, having a son who's an artist, I was hesitant-I think he was a little anxious when I bought another young man's work. But it might have encouraged him in the long run.

I went to an auction in the late '70s and bought a small Renoir. People said, "Why did you buy a Renoir that size?" I said, "I can put it in the safe with my diamonds." And that was a true story. I bought it to put it in the safe.

Don't try to buy art as an investment. Buy something you really love because you're going to have to look at it again tomorrow. And an investment can go up or down. Buy something you really adore, you really like, and you want to live with. And if you decide some years later you don't want to live with it anymore, sell it. Get out.

It's the rough diamond that dictates what you can get out of a diamond. You can't say, "I'm going to make this," or, "I'm going to make that." It's nature. Whatever nature gives us, we explore and we build on. We can't create something that is not in the stone, so we take away as many imperfections as we can. Sometimes, you can't take them all away. But mostly, our cut, our polish, the life we put into the stones, the beauty that we bring out is exceptional.