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A jewel bearing is a plain bearing in which a metal spindle turns in a jewel-lined pivot hole. The hole is typically shaped like a torus and is slightly larger than the shaft diameter. The jewels are typically made from the mineral corundum , usually either synthetic sapphire or synthetic ruby .
Pierced jewel and capstone, used as a low-friction bearing in a mechanical watch. Lubrication is provided by a small drop of oil, kept in place by capillary action. In the 1690s, Fatio discovered a method for piercing a small and well-rounded hole in a ruby, using a diamond drill.
English: Drawing of a jewel bearing and capstone in a mechanical watch. The bearing is sectioned through the axis. The jewels (red) are made of synthetic ruby. The lower jewel is called the 'hole jewel', the upper one is the 'capstone' or 'end jewel'. This type of bearing is used in watches where friction is critical, such as in the balance ...
Title page of a printed lapidary by Conrad Gessner of 1565. A lapidary is a text in verse or prose, often a whole book, that describes the physical properties and metaphysical virtues of precious and semi-precious stones, that is to say, a work on gemology. [1]
Frank Raymond "F. R." Leavis CH (/ ˈ l iː v ɪ s / LEE-vis; 14 July 1895 – 14 April 1978) was an English literary critic of the early-to-mid-twentieth century. He taught for much of his career at Downing College, Cambridge, and later at the University of York.
For watch bearings, a jewel bearing made of ruby, comprising a ring (the "hole") with a sink for oil, is invented by Nicholas Facio with Peter and Jacob Debaufre, who use pierced natural rubies. Other gemstones are used subsequently, including garnet (which is too soft) and diamond ; in the 20th century, synthetic ruby or sapphire becomes ...
The largest collection of these masterpieces was the Phoebe Boyle one; over 100 jewelled bindings were sold in 1923. Jewelled bindings occasionally appear at auction; literature on them is surprisingly scant given their superb quality. In 1998, Rob Shepherd of Shepherds Bookbinders bought both Zaehnsdorf and Sangorski & Sutcliffe.
The word jewellery itself is derived from the word jewel, which was anglicised from the Old French "jouel", [2] and beyond that, to the Latin word "jocale", meaning plaything. In British English, Indian English, New Zealand English, Hiberno-English, Australian English, and South African English it is spelled jewellery.