thumb|Quartzite can have a grainy, glassy, sandpaper-like surface
Quartzite is a hard, non-foliated metamorphic rock that forms when sandstone is subjected to heat and pressure deep within the Earth. It's valued for construction and industrial uses because of its durability and resistance to weathering, and it often has a distinctive grainy or glassy surface texture.
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thumb|Quartzite can have a grainy, glassy, sandpaper-like surface
Quartzite is a hard, non-foliated metamorphic rock that was originally pure quartz sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts, and hence quartzite is a metasandstone. Pure quartzite is usually white to grey, though quartzites often occur in various shades of pink and red due to varying amounts of hematite. Other colors, such as yellow, green, blue and orange, are due to other minerals.
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