Flint

Classification：Sedimentary Rock

Flint is equivalent to flint, but flint mainly refers to dark gray or black flint. Flint is commonly used in spoken language, flint is often used in the geological literature (regardless of color).

The ancient Flint and flint, with tinder ignition tools. It is a kind of stone, usually called Firestone. It is mostly produced on hills, and some are produced in water, which can ignite.
Flint, commonly known as "flint stone", is a relatively common siliceous rock. It is dense and hard. It is mostly gray and black. After it is broken, it has shell shaped fracture. According to its state of existence, it is divided into two types:
Layered Flint: most of them are symbiotic with phosphorous and manganese bearing clay layers. They are stratified, and the thickness of the monolayer is small, but the total thickness can be up to hundreds of meters, with the difference of lump and oolitic.
Tuberculate Flint: more prolific in limestone, there are nodular, oval, rod, disc, gourd like, irregular shape and other nodules, usually only 5-15 centimeters, large up to 1-2 meters. As a result of the hard and broken fracture, Flint is the earliest primitive man of stone stone generation, most of which are made by Flint, and Flint and iron strike will produce sparks, so it is also used as a fire tool for ancient people. In ancient China, a small piece of Flint and a steel "sickle" were used. Flint is also called flint. Flint gun is a trigger for striking gunpowder. In modern times, the hard property of Flint is used to make Flint as the raw material of grinding.
Mineral summary / Editors
Mineral name: Flint (quartz variety) Quartz var. Chert.
Chemical composition: SiO2, Si46.7%, containing different quantities of gaseous state, mechanical mixture of liquid and solid matter.
Identification characteristics: alpha quartz is characterized by its crystal shape, no cleavage, shell shaped fracture, and its hardness is characterized by its transformation from Shiying, and the illusion of six square bepyramid is maintained;
Genesis: alpha quartz is widely distributed in nature, and is the main rock forming mineral of many igneous rocks, sedimentary rocks and metamorphic rocks. Beta quartz occurs in acidic igneous rocks or shallow rocks, and often occurs in phenocrysts. It belongs to colloidal products of low-temperature hydrothermal fluids, mainly produced in pores of extrusive rocks.
Famous origin: widely distributed all over the world.
The origin of the name is German "quarz", which is derived from the unknown meaning.
Crystal morphology: the three party cube surface is similar to the body crystal class, and often develops into intact columnar crystal. The common form is: six square column m, rhombohedral R and Z, three party double cone s and three party square surface x, etc., the cylinder has cross striation.
Crystal structure: crystal system and space group: alpha quartz belongs to three square crystal system, P312; beta quartz belongs to six square crystal system, P622;
Unit cell parameters: alpha quartz: a0=4.91, c0=5.40; beta quartz: a0=5.01, c0=5.47;
Powder diffraction data: 3.342 (1) 4.257 (0.22) 1.8179 (0.14)
Physical property：
Hardness: 7
Proportion: 2.53g/cm3
Cleavage: no cleavage
Seashore fracture
Color: pure alpha quartz colorless, with various colors due to pigmented ions or color centers; beta quartz is usually gray, white.
Streak: colorless or white
Transparency: transparency
Luster: waxy luster
Luminescence: friction phosphorescence
Other: the piezoelectricity of alpha quartz
Optical properties:
Uniaxial crystal (+), No=1.543-1.545, Ne=1.552-1.554, double reflectivity =0.0090..