Milky quartz

Others include pink (rose), purple, and milky quartz, but most coarse crystalline quartz is colorless and transparent. Sandstone is a ready example of granular quartz. Color is a result of the presence of small amounts of metal cations such as calcium, iron, magnesium, and aluminum. 

Milky quartz is typically opaque and whitish in color because it contains microscopic bubbles or fluid-filled cavities that scatter light rather than allowing it to pass through as it would in a clear crystal. 

Milky quartz Milky- to grayish-white, translucent to opaque Common as vein-filling or irregular masses rare as crystals... 

Fluid inclusions occur either as primary inclusions within the quartz of the silicified zone (I, 11 and III), or secondary inclusions in milky quartz of the silicified zone (I and II) 5 and 10 cm far from the intrusive contact. 

The two forms on the left are formed by beta quartz, but are also formed, although not commonly, by alpha quartz. Quartz forms a large number of colored varieties, including rose quartz, amethyst, smoky quartz, citrine (Ught-yellow), and milky quartz. Inclusions such as rutile and hematite are fairly common. It also exists in a large number of varieties that exhibit no macroscopic crystalline structure. These include chalcedony, agate, flint, chert, and jasper. 

Minerals containing liquid inclusions may explode owing to the evolution of steam during heating. Other such as baryte break into smaller crystal while milky quartz breaks into very fine powder or dust. 

The mostly difficult problems in quartz sorting are quartz-feldspar ores and differentiation of vein quartz into transparent and milky varieties, hi the first case LIBS separation may be effective using A1 emission lines present in feldspar, which are absent in quartz (Fig. 8.7). 

It is not clear why a basic quinoline system dissolves more quartz than a basic aqueous system, especially since potassium hydroxide is not readily soluble in quinoline. Attempts to dissolve potassium hydroxide in quinoline result in a dense milky suspension. The suspension may contain the active agent, perhaps a quaternary organic salt, that serves as a better hydroxyl source than solid potassium hydroxide in water. Practical grade quinoline was used for these experiments, and this may contain enough water for dissociation. 

Quartz Pyrolysis Tube—The suggested maximum temperature for a quartz pyrolysis tube is 1200 C. Samples containing alkali-metals (elements from the Periodic Group lA (that is, Na, K, etc.)) or alkaline earths (elements from the Periodic Group IIA (that is, Ca, Mg, etc.)) will cause quartz to devitrify (that is, become milky white and brittle). 

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