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An early use of the piezoelectricity of quartz crystals was in phonograph pickups. One of the most common piezoelectric uses of quartz today is as a crystal oscillator. The quartz oscillator or resonator was first developed by Walter Guyton Cady in 1921. [92] [93] George Washington Pierce designed and patented quartz crystal oscillators in 1923.
The novaculites are milky-white, thinly-bedded cherts of great hardness; they underwent a low-grade metamorphism during the Ouachita orogeny. Their mineralogy consists of microquartz with a grain-size of 5 to 35 μm. The microquartz is derived from the sclerae of sponges and the tests of radiolarians.
Amethyst (purple variety of quartz) Ametrine (variety of quartz) Ammolite (organic; also a gemstone) Amosite (asbestiform grunerite) Antozonite (variety of fluorite) Anyolite (metamorphic rock - zoisite, ruby, and hornblende) Aquamarine (light blue variety of beryl) Argentite (high temperature form of acanthite) Asbestos (fibrous serpentine- or ...
Glassy, translucent, gray-tan, pseudohexagonal zunyite crystals on a milky quartz matrix. From the Big Bertha Mine, Dome Rock Mountains, La Paz County, Arizona (size: 3.3 x 3.2 x 2.8 cm)) Zunyite occurs in highly aluminous shales and hydrothermally altered volcanic rocks.
Omphacite is a member of the clinopyroxene group of silicate minerals with formula: (Ca, Na)(Mg, Fe 2+, Al)Si 2 O 6.It is a variably deep to pale green or nearly colorless variety of clinopyroxene.
The geologic history of these crystals began about 500 million years ago in a shallow sea which was receiving sediments from the ancient Adirondack Mountains to the north. The calcium and magnesium carbonate sediments accumulated and lithified to form the dolomite bedrock currently known as the Little Falls Formation and formerly as the Little ...
Late-stage charnockite dykes cutting anorthosite, Rogaland, Norway Job Charnock's Mausoleum at St John's Church compound, Kolkata. Charnockite (/ ˈ tʃ ɑːr n ə k aɪ t /) is any orthopyroxene-bearing quartz-feldspar rock formed at high temperature and pressure, commonly found in granulite facies’ metamorphic regions, sensu stricto as an endmember of the charnockite series.
The 23rd edition is now in print under the title Manual of Mineral Science (Manual of Mineralogy) (2007), revised by Cornelis Klein and Barbara Dutrow. Equally influential was Dana's System of Mineralogy, first published in 1837, which has consistently been updated and revised. The 6th edition (1892) [27] being edited by his son Edward ...