The first time I saw tadelakt was in St. Tropez, France, several years ago. I was immediately transfixed by the pearlescent, translucent, hand-rubbed-all-the-way-to-glossy, impervious-to-water finish. I had never seen anything like it before, and rarely have since. I had stumbled upon one of the oldest and most treasured plaster finishes in the world. The art of tadelakt is 4,000 years old, and comes from Morocco. Designers in France are using it today for its silky texture and indescribable…