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Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at . Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classified as gemstones. Since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Eurasia. Quartz is the mineral defining the value of 7 on th

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The effect of an elastic deformation on optical properties of an aeolotropic medium (piezo-optic effect) is explicitly established from an energy function. Then is deduced the number of distinct coefficients ruling this effect in the special case of quartz. The author gives a new method to measure the absolute dephasage ; method based on photometric exploration of the three beams diffracted image, around the focus. By this method a phase variation of 2π/2000 has been disclosed. This method has been used for the direct measure of plaza-optic effect in quartz. With a single type of cubic sample, 5 out of the 8 coefficients of quartz have been accurately settled, and an upper limit has been given for the one of others. Other applications of this measurement method are considered.

s.n.1956

Fracture toughness measurement in fused quartz using triangular chevron-notched micro-cantilevers

Lionel Michelet, Andreas Mortensen, Martin Guillermo Mueller, Václav Pejchal, Goran Zagar

We extend to flat surfaces the fracture toughness method presented in Acts Materialia vol. 86 (2015) p.385 and measure in this manner the fracture toughness of fused quartz. Tests give 0.67 +/- 0.01 MPa m(1/2) which agrees with earlier microscopic and macroscopic test data for the fast fracture toughness of this material. Data show no signs of sub-critical crack growth; this observation is at variance with what one would expect from literature data on the phenomenon. (C) 2015 The Authors. Published by Elsevier Ltd.

Elsevier2016

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2018

MSE-302: Phase transformations

Ce cours est une introduction aux transformations de phases liquide-solide et solide-solide. Il aborde les aspects thermodynamiques et cristallographiques. Il traite principalement des matériaux métalliques, et établira des ponts vers les céramiques et la minéralogie.

CH-450: Solid state chemistry and energy applications

You will learn about the bonding and structure of several important families of solid state materials. You will gain insight into common synthetic and characterization methods and learn about the applicability of several classes of materials in energy relevant applications.

ChE-410: Catalysis for emission control and energy processes

The course is an introduction to heterogeneous catalysis for environmental protection and energy production. It focusses on catalytic exhaust gas cleaning as well as catalytic systems relevant for gaseous and liquid fuel production. The course ends with two days of experimental exercises at PSI.

Mineral

In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally

Crystal

A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that exte

Silicon dioxide

Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand.