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This is also known colloquially as shocked quartz. [8] Material properties (size, color, texture) of fulgurites vary widely, depending on the size of the lightning bolt and the composition and moisture content of the surface struck by lightning. Most natural fulgurites fall on a spectrum from white to black.
The presence of shocked quartz supports that such craters were formed by impact, because a volcanic eruption would not generate the required pressure. [2] Lightning is now known to contribute to the surface record of shocked quartz grains, complicating identification of hypervelocity impact features. [3]
By applying a coat of electrolytic solution to the surface of the wood, the resistance of the surface drops considerably. Two electrodes are then placed on the wood and a high voltage is passed across them. Current from the electrodes will cause the surface of the wood to heat up until the electrolyte boils and the wooden surface burns.
Metamorphism takes place at temperatures in excess of 150 °C (300 °F), and often also at elevated pressure or in the presence of chemically active fluids, but the rock remains mostly solid during the transformation. [1] Metamorphism is distinct from weathering or diagenesis, which are changes that take place at or just beneath Earth's surface ...
Quartz is, therefore, classified structurally as a framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. [10] Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation ...
Fused quartz is a glass made from chemically pure silica. [68] It has very low thermal expansion and excellent resistance to thermal shock, being able to survive immersion in water while red hot, resists high temperatures (1000–1500 °C) and chemical weathering, and is very hard.
A surface plate is a solid, flat plate used as the main horizontal reference plane for precision inspection, marking out (layout), and tooling setup. [1] The surface plate is often used as the baseline for all measurements to a workpiece, therefore one primary surface is finished extremely flat with tolerances below 11.5 μm or 0.0115 mm per ...
Evidences of the effect of lightning on rock are the presence of beta-quartz (T > 573 °C (1,060 °F), called "flashstones" by local diggers), melted barbed wires (T > 1,500 °C or 2,730 °F); furrows in soils and colluvium up to 120-metre (394 ft) long with the presence of cristobalite, the high-temperature modification of quartz (1,713–18 ...