What is a Galuchat watch band?

I first started noticing Galuchat watch straps on De Grisogono timepieces. A sort of bubbly textured look. But what is it?
Also known as Shagreen, Galuchat is actually either sharkskin or stingray skin. The name comes from Jean-Claude Galuchat who was Louis XV's master leather artisan. He introduced this exotic leather to France in the 18th century where he was most noted for his sheaths. He fashioned shagreen for Louis XV and his court. He placed it on objects such as snuff boxes, wig cases, furniture, jewelry boxes and toilette items. It is said Madame de Pompadour was a great fan of Shagreen.
Jean-Claude Galuchat, although the most renowned for his use of shark skins, was not the first. Shark and sting ray skins were used as early as the 8th century. The Japanese Tachi, Katana and Wakizashi used the undyd untreated skins for sheaths and hilts of swords. The rough texture of the material provided the handle with extra grip as well as high resilience. In the China Qing dynasty, the polished Shagreen were used for composite bows. In the 19th century the material was used for book bindings and pocketbooks.
The name Shagreen actually refers to rough untamed skin. The leather was most often made from a horses back and most often dyed green. Today's Shagreen is made for Galuchat which is shark or sting ray skin. Shagreen is from the French word chagrin which means sorrow or Turkish sagri meaning "the back of a horse". As the leather was rough in texture the word was synonymous with displeasure or ill humor.
None the less, Galuchat still holds a unique quality. The uniqueness comes from round calcified papillae called "placoid scales". These placoid scales are otherwise known as Denticles and are small outgrowths which cover the skin of many cartilaginous fish such as sharks and sting rays. The denticles are similar in structure to teeth.
Most often the placoid scales are polished down until the denticles are rounded and pearl like.
De Grisogono has taken the natural texture of the Galuchat and enhanced it with exceptional colors and polishing, creating a timepiece where the strap commands as much attention as the watch.