Quartz, a professional term in geology, generally refers to low-temperature quartz (α-quartz), which is the most widely distributed mineral in the quartz group. Quartz in a broad sense also includes high-temperature quartz (β-quartz), coesite, and the like. The main component is SiO2, which is colorless and transparent, often contains a small amount of impurities, and becomes a translucent or opaque crystal with a hard texture. Quartz is a mineral resource with very stable physical and chemical properties, and the crystal belongs to the oxide mineral of the trigonal system. Quartz block, also known as silica, is mainly the raw material for the production of quartz sand (also known as silica sand), as well as the raw material for quartz refractories and sintering ferrosilicon.
The professional names of quartz minerals and rocks include quartz, crystal, opal, flint, flint, agate, diatomite, quartz sandstone, siliceous rock, quartzite, etc. The market application names are quartz ore, vein quartz, lard stone, quartz sand, silica sand, quartz powder, microsilica, sea sand, river sand, foundry sand, glass sand, diatomite, crystal, agate, etc.
Quartz has different names due to different origins
The morphological and physical properties of quartz have changed into many variants. For example, there are three homogeneous polymorphic variants of quartz, tridymite, and cristobalite, each of which has two variants, α and β;
There are three types of genesis: magma, sedimentation and metamorphism, as follows:
(1) The origin of magma is called: vein quartz, quartz or siliceous rock;
(2) Sedimentary origins are called: quartz sandstone or sedimentary quartz sandstone, etc., colloidal deposits are called siliceous rocks, siliceous strips, siliceous clusters, siliceous concretions, etc., and biologically deposited siliceous rocks are called It is diatomite; in addition to the cemented deposits of hundreds of millions of years and tens of millions of years of conventional geological history, the original rock was weathered, transported and deposited in modern coastal, rivers, lakes, sandy land and other loose and unconsolidated sediments, which are called coastal sands , river and lake sand, dune sand, powder quartz, etc., as follows:
Coastal sand: The sand that has been weathered, transported and deposited on the modern coast is called coastal sand or silica sand. The main component is quartz, and a small part is feldspar. The mineral composition and chemical composition are relatively simple. Coastal placer resources are one of the largest potential mineral resources. At present, there are more than 30 kinds of coastal placer mines being exploited and utilized abroad, and their reserves and output are very important. For example, 98% of the world’s rutile, 96% of zircon and 50% of ilmenite reserves are from placer. In terms of the proportion of mining volume to world production, ilmenite placer ore accounts for 30%, monazite placer ore accounts for 80%, rutile placer ore accounts for 98%, zircon placer ore accounts for 90%, cassiterite placer ore (excluding China) accounted for 70%, placer gold accounted for 5% to 10%, diamond placer accounted for 5.1%, and platinum placer accounted for 3%. Therefore, the coastal placer mine is a potential mineral resource in the forefront after oil and natural gas in the treasure house of marine mineral resources.
River and lake sand: The sand that the original rock has been weathered, transported and deposited in modern rivers or lakes is river and lake sand, the main component is quartz, and the others are feldspar, granite, limestone, etc. And the influence of chemical composition, chemical composition and mineral composition are more complex.
Dune Sand: Sand formed by the detrital material transported by the river and transported and accumulated by the wind for a short distance, called dune sand, the main component is quartz, and the others are kaolin, etc.;
Powdered quartz (silica): It is formed by the accumulation of siliceous rocks through weathering and leaching to form powdery and earthy substances, mainly composed of quartz and clay minerals, with high SiO2 content, about 60%-80%, Al2O3 10%-20% , Fe2O32% to 3%, the mineral composition is not only silt grade a crystalline quartz, but also contains some clay minerals, such as kaolinite, illite, hydromica and montmorillonite, etc. The particle size is generally 1-10 μm, showing Unimodal distribution, with a peak value of 5-8 μm, is called silica; residual powdery or earthy siliceous material is formed from tunnel stone or siliceous limestone by weathering, leaching and decomposing. The mineral composition is very simple, and the quartz content can reach 98 %, the content of Al2O3 and Fe2O3 is small, the composition is simple, almost all of them are a-crystalline quartz, without clay minerals, the particle size is bimodal distribution, the fine-grained grade is 5-45μm, and the coarse-grained grade is 0.25-10mm (coarse-grained). The latter is the product of incomplete weathering), and the peaks are 5-20 μm and 1-4 mm respectively, which are called powder quartz. 70 mesh-120 mesh quartz sand powder.
(3) Quartzite of metamorphic origin: quartz sandstone, argillaceous or calcareous quartz sandstone, colloidal sedimentary siliceous rock (including terrigenous clastic dissolved and redeposited siliceous rock and siliceous rock related to volcanic eruption) and deep-sea radiation Quartzite is formed by regional metamorphism and recrystallization, such as siliceous rock, or quartzite is formed by thermal contact metamorphism of siliceous rock, and the metamorphic quartz is called quartzite.
Quartz in Different People’s Eyes
1. First, for geology professionals, the genetic classification of quartz mineral rocks is still maintained, namely magmatic vein quartz and siliceous rock, sedimentary quartz sandstone, siliceous rock, diatomite and coastal sand, river and lake Sand, dune sand, powder quartz, silica and metamorphic quartzite; for single quartz minerals, keep the names of variant tridymite, cristobalite, crystal, chalcedony, flint, agate, opal, opal, etc.; understand siliceous minerals Rock market names, such as silica sand, quartz sand, quartz powder, microsilica, sea sand, river and lake sand, dune sand, silica and powder quartz, etc.
2. For mine owners and users of siliceous mineral rock raw materials, the common and easy-to-understand names formed in the process of mine development and market application, such as quartz with obvious grease luster is called lard stone; vein quartz, sedimentary quartz sandstone , siliceous rock, quartzite and other crushed and processed sand with different particles are called quartz sand or silica sand; quartz sand used in the foundry industry is called foundry sand, and quartz used in the glass industry is called glass sand; The finer quartz powder of 325 mesh and above is called microsilica; the sand extracted from the ocean is called sea sand; the sand extracted from rivers or lakes is called river-lake sand; sandy sand is called dune sand.