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Gypsum crystals are soft enough to bend under pressure of the hand. Sample on display at Musée cantonal de géologie de Lausanne. Gypsum is moderately water-soluble (~2.0–2.5 g/L at 25 °C) [ 13 ] and, in contrast to most other salts, it exhibits retrograde solubility , becoming less soluble at higher temperatures.
It forms crystals in the isometric system very similar to normal rock salt, halite (NaCl). The two are, in fact, isomorphous. [5] Sylvite is colorless to white with shades of yellow and red due to inclusions. It has a Mohs hardness of 2.5 and a specific gravity of 1.99. It has a refractive index of 1.4903. [6]
where Ur is the modulus of resilience, σy is the yield strength, εy is the yield strain, and E is the Young's modulus. [1] This analysis is not valid for non-linear elastic materials like rubber, for which the approach of area under the curve until elastic limit must be used.
Normal metals, ceramics and most crystals show linear elasticity and a smaller elastic range. Linear elastic deformation is governed by Hooke's law, which states: = where σ is the applied stress; E is a material constant called Young's modulus or elastic modulus; ε is the resulting strain.
The first crystals were found in a pegmatite found near Rumford, Maine, US, and in Minas Gerais, Brazil. [53] The crystals found are more transparent and euhedral, due to the impurities of phosphate and aluminium that formed crystalline rose quartz, unlike the iron and microscopic dumortierite fibers that formed rose quartz. [54]
Emoto claimed that water was a "blueprint for our reality" and that emotional "energies" and "vibrations" could change its physical structure. [14] His water crystal experiments consisted of exposing water in glasses to various words, pictures, or music, then freezing it and examining the ice crystals' aesthetic properties with microscopic photography. [9]
A crystal's crystallographic forms are sets of possible faces of the crystal that are related by one of the symmetries of the crystal. For example, crystals of galena often take the shape of cubes, and the six faces of the cube belong to a crystallographic form that displays one of the symmetries of the isometric crystal system. Galena also ...
Psychological resilience, or mental resilience, is the ability to cope mentally and emotionally with a crisis, or to return to pre-crisis status quickly. [1]The term was popularized in the 1970s and 1980s by psychologist Emmy Werner as she conducted a forty-year-long study of a cohort of Hawaiian children who came from low socioeconomic status backgrounds.