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.

You learn about yourself when you're collecting art. You learn what you're capable of. After all, we're not speaking about pennies-we're speaking about vast sums of money. I do it on my own back without advice, so I've got the confidence to do it.

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.

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.

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.

When there's an opportunity, some people pass it by. I've been lucky enough to recognise opportunities and every day, in my business, there's an opportunity somewhere - to buy, expand, design.

One of the great things about collecting contemporary art is that you mix with contemporary people.