Crossword clues for quartzite
The Collaborative International Dictionary
Quartzite \Quartz"ite\, n. [Cf. F. quartzite.] (Min.) Massive quartz occurring as a rock; a metamorphosed sandstone; -- called also quartz rock.
Douglas Harper's Etymology Dictionary
1837, from quartz + -ite.
Wiktionary
n. a metamorphic rock consisting of interlocking grains of quartz
WordNet
n. hard metamorphic rock consisting essentially of interlocking quartz crystals
Wikipedia
Quartzite (from ) is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to grey, though quartzites often occur in various shades of pink and red due to varying amounts of iron oxide (FeO). Other colors, such as yellow, green, blue and orange, are due to other mineral impurities.
When sandstone is cemented to quartzite, the individual quartz grains recrystallize along with the former cementing material to form an interlocking mosaic of quartz crystals. Most or all of the original texture and sedimentary structures of the sandstone are erased by the metamorphism. The grainy, sandpaper-like surface becomes glassy in appearance. Minor amounts of former cementing materials, iron oxide, silica, carbonate and clay, often migrate during recrystallization and metamorphosis. This causes streaks and lenses to form within the quartzite.
Orthoquartzite is a very pure quartz sandstone composed of usually well-rounded quartz grains cemented by silica. Orthoquartzite is often 99% SiO with only very minor amounts of iron oxide and trace resistant minerals such as zircon, rutile and magnetite. Although few fossils are normally present, the original texture and sedimentary structures are preserved.
The term is also traditionally used for quartz-cemented quartz arenites, and both usages are found in the literature. The typical distinction between the two (since each is a gradation into the other) is a metamorphic quartzite is so highly cemented, diagenetically altered, and metamorphosized so that it will fracture and break across grain boundaries, not around them.
Quartzite is very resistant to chemical weathering and often forms ridges and resistant hilltops. The nearly pure silica content of the rock provides little for soil; therefore, the quartzite ridges are often bare or covered only with a very thin layer of soil and (if any) little vegetation.
Usage examples of "quartzite".
The rock was stained red, with veins of white quartzite and schist, the first sign of an underlying pegmatite structure.
Ribeiro immediately began his own investigations, and in many localities found flakes of worked flint and quartzite in Tertiary beds.
In 1871, Ribeiro presented to the Portuguese Academy of Science at Lisbon a collection of flint and quartzite implements, including some gathered from the Tertiary formations of the Tagus valley.
Most of the tools discovered by Hrdlicka and Ameghino during their joint expedition were roughly chipped from quartzite pebbles.
The surrounding hills were dotted with sparkling homes of those most successful under the new democracy, homes of quartzite and white marble, nestled in thick forests of tall trees.
Even fewer watched from verandas overlooking the city as midnight approached, verandas of great homes in marble and quartzite high up in the surrounding hills.
Clutching the fist-sized piece of quartzite in his hand, he scampered down the bank and headed for the muddy river.
Round, flattened, or disk-shaped quartzite pounders, medium and small sizes.
A stone bowl or basin made from an oblong, somewhat oval-shaped quartzite slab, and used for pounding and grinding mesquite beans.
I came out onto the promenade deck I glanced through the quartzite windows.
From where I stood I could see through the quartzite side of the promenade deck above and beyond the airlock, while I was able at the same time to run a speculative eye over the passengers leaving and arriving.
Thanks be it was during the sleep-hours, else we would have had eager, excited, curious, perhaps fearful passengers peering at us across the gap from the quartzite windows.
As they passed I could see the side of the deck and the quartzite windows and even a star or two in the black void beyond, just as if they were transparent, made of glass themselves.
She pointed to the quartzite windows that gave us a view of empty space and the stars beyond.
Fifteen paces on, they stumbled into an outcropping of quartzite or some other crystalline mineral that resisted the erosive wind.