| Quartz paramorphs after tridymite are absent from Fiachanis but present in the three Priomh-lochs samples adjacent to late minor intrusions. |
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| The abundant and ubiquitous quartz paramorphs after tridymite in the walls attest to a very shallow emplacement depth. |
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| Natural quartz can be accompanied by other crystalline silica phases, as tridymite and cristobalite with identical chemical formula. |
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| The crystals, called cristobalite and tridymite, swim in clouds around stars just before they begin to form planets. |
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| Cristobalite has the same chemical composition as coesite, stishovite, quartz, and tridymite but has a different crystal structure. |
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| Both tridymite and cristobalite are considered more fibrogenic to the lungs than quartz. |
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| This Good Practices Guide only covers three of the different forms of crystalline silica, i.e. the minerals quartz, cristobalite and tridymite. |
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| If there is sufficient softening on the surface of the sand grains to create a liquid, tridymite will be formed. |
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| Natural tridymite has no specific commercial use. |
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| Cristobalite and tridymite are not abundant in nature. |
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| This mineral is unique to the andesitic volcanic complex, occurring in association with tridymite, hematite, cassiterite, magnetite, orpiment and realgar. |
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| Tridymite also forms in contact-metamorphosed rocks. |
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