Martine,
I heard Art Seymour asked that exact question by someone at the Tucson and I truly loved his reply "About forty years". For me its "About thirty six years" seeing as though I made my first stone beads in 1979.

In all reality it takes hours and hours, I told a friend that if someone were to come to watch me make a bead like this they would leave out of boredom just waiting for the hole to be drilled, and this would come after cutting the bead blank from the piece of rough stone.

I used to keep strict track of the time I spent on my projects but then it dawned on me that I was after the finished piece and it pretty much did not matter how long it took. The most time I ever spent on a piece I kept track of the time on was around 160 hours this was a necklace and not just beads. I think it was the piece in the image below, this piece was made around late 1984 or early 1985. The beads in this piece were 3/8 inch in diameter to give you an idea of how small the pendent is.

All my best .... Danny