Unmounted Jewels The Diamond

History Of Watches ... Peter Hele, still a young man, fashions works which even the most learned mathematicians admire. He shapes many-wheeled clocks out of small bits of iron, which run and chime the hours without weights for forty hours, whether carried at the breast or in a handbag and because he was popularized in a 19th century novel...

Gemstone ... In modern times gemstones are identified by gemologists, who describe gems and their characteristics using technical terminology specific to the field of gemology. The first characteristic a gemologist uses to identify a gemstone is its chemical composition...