Encyclopedia of Glass Science, Technology, History, and Culture. Группа авторов. Читать онлайн. Newlib. NEWLIB.NET

Автор: Группа авторов
Издательство: John Wiley & Sons Limited
Серия:
Жанр произведения: Техническая литература
Год издания: 0
isbn: 9781118799499
Скачать книгу
it. The fashion for glass was such that a German living in Paris named Beyer presented in 1785 to the Académie des Sciences his forte‐piano with glass plates, acted upon by wool‐covered hammers, which Franklin christened glass‐cord [17]. And it was a flute made from lead‐crystal glass that the Parisian instrument maker Claude Laurent (d. 1848) patented in 1806 and produced in white, cobalt‐blue, and uranium‐green hues; in spite of its weight, its musical qualities and reduced temperature‐induced pitch changes ensured its popularity for several decades [18].

      This select series of anecdotes probably makes it unnecessary to emphasize again the importance of glass in daily and social life stressed above by Bontemps and Figuier. It might in contrast be useful to mention that the antique tradition or ornamental glass was revived at the same period by Georges Frédéric Strass (1701–1773), who became the French King's jeweler, when he invented strass, or rhinestone, a high‐lead crystal glass bearing various metal oxides that is still made today to imitate precious stones.

      1.4 The Silica Paradoxes

      1.4.1 Biogenic Silica vs. Flint

Photo depicts the abundant beds of black flint present in a 80-m high limestone cliff of the English Channel at the Pointe du Chicard in Yport. Same beds of the Upper Cretaceous used in the past for making flint glass in England on the other side of the Channel. Height visible on the picture: 10 m.

      Source: Photo P. Richet.

      1.4.2 A Quantum‐Chemical Factory: The Production of Silica Sand

      Although glassmaking would have been possible without sand, it is unlikely that flint would have led to the invention of glass as it requires thorough grinding to become a reactive raw material. Regardless of grinding costs, it is also doubtful that flint would have been a silica resource widespread and convenient enough for an expanding glass industry. The fundamental importance of silica sand thus remains undisputed. Geologically, sand is produced via the weathering of granite and related SiO2‐rich igneous rocks. The most abundant rock of the Earth's crust, granite is made up of quartz and alkali [(Na,K)AlSi3O8] and plagioclase [(Nax,Ca1 − x)Al2 − xSi2 + xO8] feldspars. Whereas feldspars progressively transform into clay under the action of meteoric waters, quartz resists and accumulates as sand either on the spot or downstream.