When devitrifying silica, cristobalite is usually the first phase to form, even when well outside of its thermodynamic stability range.
12.
Quartz has several polymorphs, including tridymite and cristobalite at high temperatures, high-pressure coesite, and ultra-high pressure stishovite.
13.
Silicosis is a fibrosing interstitial lung disease caused by inhaling fine particles of silica, most commonly in the form of quartz or cristobalite.
14.
Powder diffraction can distinguish between minerals that may appear the same in a hand sample, for example quartz and its polymorphs tridymite and cristobalite.
15.
In Pahrump Hills, an area about 39 feet lower, the minerals clay, hematite, jarosite, quartz, and cristobalite were found.
16.
Non-fibrous particulate materials that cause cancer include powdered metallic cobalt and nickel, and crystalline silica ( quartz, cristobalite, and tridymite ).
17.
Minerals formed by alteration processes include alunite, calcite, cristobalite, illite, jarosite, kaolinite, pyrophyllite, quartz, smectite, sulfur and tridymite.
18.
What appears to happen is that symmetry reduces the number of constraints so that structures such as quartz and cristobalite are slightly floppy and thus support some RUMs.
19.
Other contaminants-- cristobalite, barium, cadmium, copper, zinc and mercury-- exceeded the levels in fewer than 5 percent of the samples tested.
20.
For example, quartz will change into a variety of its SiO 2 polymorphs, such as tridymite and cristobalite at high temperatures, and coesite at high pressures.
