From the point of view of chemical composition, the quartz mineral rock is mainly SiO₂; from the point of view of mineral composition, it is mainly crystalline or cryptocrystalline quartz. However, siliceous mineral rocks have many names, which are very unfavorable for research and application. It is very necessary to comprehensively classify and name siliceous mineral rocks by considering professional research and market applications.
1、How many names and types does quartz have？
The professional names of quartz mineral rocks include quartz, crystal, opal, flint, agate, diatomite, quartz sandstone, siliceous rock, quartzite, etc. The market application names include raw quartz ore, vein quartz, lardstone, quartz sand, silica sand, quartz powder, silica powder, sea sand, river sand, foundry sand, glass sand, diatomaceous earth, crystal, agate, etc., the numerous names because of the following 3 reasons:
1).The morphology and physical properties of quartz have changed into many variants. For example, there are three homogeneous and multi-morphic variants of quartz, quartz, tridymite, and cristobalite. Each variant has two variants of α and β; coarse-grained quartz crystal changes itself There are crystal, amethyst, smoky crystal, citrine, rose crystal, blue quartz, milk quartz, grass crystal, Venus stone, opal, tiger’s eye, eagle’s eye, etc.; quartz cryptocrystalline variants include chalcedony, Chalcedony, agate, flint, jasper, opal, precious opal, fire opal, wood opal, glass opal, water opal, pearl opal, opal, diatomaceous earth, etc.
2).The origin of quartz is different, so the name is different. There are three kinds of origin: magma, sedimentation and metamorphism. The details are as follows:
（1）The origin of magma is called vein quartz, quartz or siliceous rock;
（2）Sedimentary genesis is called quartz sandstone or sedimentary quartz sandstone, colloidal deposition is called siliceous rock, siliceous strip, siliceous mass and siliceous nodule, and biological deposition is called diatomite. Besides cemented deposition for hundreds of millions of years or tens of millions of years in conventional geological history, the original rock is weathered and transported and deposited in modern coastal, river, lake and sandy land in a loose and unconsolidated state They are called seashore sand, river lake sand, sand dune sand, silty quartz, etc.
Coastal sand: The sand that the original rock has been weathered, transported and deposited in the modern coastal area is called coastal sand or silica sand. The main component is quartz, and a small part is feldspar. The mineral and chemical components are relatively simple. Coastal placer resources are one of the largest potential mineral resources. At present, more than 30 types of coastal placer deposits are being exploited abroad, and their reserves and output occupy a very important position. For example, 98% of rutile, 96% of zircon and 50% of ilmenite reserves in the world come from placers. In terms of the proportion of mining volume in the world output, ilmenite placer accounts for 30%, monazite placer accounted for 80%, rutile placer accounted for 98%, zircon placer accounted for 90%, and cassiterite placer (excluding China) accounted for 70%, gold placer 5%-10%, diamond placer 5.1%, and platinum placer 3%. Therefore, the coastal placer is a potential mineral resource second only to oil and natural gas in the treasure house of marine mineral resources.
River lake sand: the sand whose original rock has been weathered, transported and deposited in modern rivers or lakes is river lake sand, mainly composed of quartz, feldspar, granite, limestone, etc. it is affected by the mineral composition and chemical composition of rocks around rivers or lakes, and the chemical composition and mineral composition are relatively complex.
Sand dune: the sand formed by the short distance transportation and accumulation of clastic materials transported by river and blown by wind. It is called sand dune. It is mainly composed of quartz and kaolin;
Silty quartz (siliceous clay): it is composed of siliceous rocks accumulated by weathering and leaching to form powdery and earthy materials. It is mainly composed of quartz and clay minerals.The content of SiO₂ is relatively high, about 60%-80%, and Al₂O₃10%-20% , Fe₂O₃ 2% to 3%. In addition to silt grade a crystalline quartz, the mineral composition also contains a part of clay minerals, such as kaolinite, illite, hydromica and montmorillonite. The particle size is generally 1-10μm. Single-peak distribution, with a peak value of 5-8μm, called silica; it is composed of tunnels or siliceous limestone through weathering and leaching to form residual powdery or earthy siliceous materials. The mineral composition is extremely simple, and the quartz content can reach 98 %, the content of Al₂O₃ and Fe₂O₃ is small, the composition is simple, almost all a crystalline quartz, without clay minerals, the grain size is bimodal, the fine grain grade is 5-45μm, the coarse grain grade is 0.25-10mm (coarse grain Those are the products of incomplete weathering), the peak values are 5-20μm and 1-4mm respectively, which are called powder quartz.
（3）Metamorphic quartzite: quartz sandstone, argillaceous or calcareous quartz sandstone, colloidal sedimentary siliceous rock (including terrigenous clastic dissolution and redeposited siliceous rock and siliceous rock related to volcanic fumarole) and deep-sea radiolarian siliceous After regional metamorphism and recrystallization of rock, quartzite is formed, or siliceous rock is transformed into quartzite through thermal contact. The quartz of metamorphic origin is called quartzite;
3).There are many easy-to-understand names for mine owners and siliceous mineral rock materials in mine development and market application. For example, the quartz with obvious grease luster is called lard; vein quartz, sedimentary quartz sandstone, siliceous rock, and quartzite The sand that is crushed and processed into different particles is called quartz sand or silica sand; the quartz sand used in the foundry industry is called foundry sand, and the quartz used in the glass industry is called glass sand; the finer 325 mesh and above Quartz powder is called silica powder; sand extracted from the ocean is called sea sand; sand extracted from rivers or lakes is called river and lake sand; sandy sand is called dune sand.
2、Quartz names should be unified as follows
The first is to maintain the genetic classification of quartz minerals and rocks for geological professionals, that is, magmatic vein quartz and siliceous rock, sedimentary quartz sandstone, siliceous rock, diatomite and coastal sand, river lake sand, sand dune sand, silty quartz, siliceous soil and metamorphic quartz rock; for single quartz mineral, to maintain variant quartz, cristobalite, crystal, chalcedony, flint and quartz. Know the market names of siliceous minerals and rocks, such as silica sand, quartz sand, quartz powder, silica micropowder, sea sand, river lake sand, sand dune, siliceous soil and silty quartz.
Secondly, for the owners, users and managers of quartz mineral raw materials, the origin of quartz minerals and rocks will not be subdivided. For the continental massive siliceous minerals and rocks, the raw ore is collectively referred to as quartz, the weathered loose quartz is collectively referred to as silty quartz, and the mines are collectively referred to as quartz mines. For the marine siliceous minerals and rocks, the main sand is referred to as coastal sand. For the rivers and lakes, the siliceous minerals and rocks are collectively referred to as silty quartz The main sand is called river lake sand; the sand formed by the short-distance transportation and deposition of river transported clastic materials by wind is called sand dune sand; for the managers of quartz minerals and rocks, the name is unified as quartz raw material, and the statistical reserves are slightly subdivided, and the quartz raw materials are divided into quartz, crystal, chert, agate, opal, coastal sand, river lake sand, sand dune sand and silty quartz (siliceous soil) The reserves, output, sales volume, market price, etc. are calculated respectively, instead of the current simple mineral reserves statistical name “glass siliceous raw material” (the main raw material for glass production is siliceous rock (sand), and the general glass siliceous raw material accounts for about 70% of the raw material composition. Dolomite, limestone, feldspar, soda ash, mirabilite, carbon powder and other ingredients are added to melt, shape and retreat Fire, cutting and other processes from a variety of glass products.
Glass siliceous raw materials refer to siliceous rocks (sands) that can be used as glass raw materials. In the detailed rules for the implementation of the mineral resources law of the people’s Republic of China for the classification of mineral resources (1994), glass siliceous raw materials refer to four kinds of quartz sandstone, quartzite, vein quartz and quartz sand used for glass of separate minerals.
Because ordinary river sand is mainly used for road and house construction, it is difficult to make statistics, and the physical and chemical properties of quartz are not fully reflected in the application, so it is recommended not to be included in the statistical items; the application is collectively referred to as various mesh quartz sand and quartz powder, such as 20 mesh quartz sand, 40-70 mesh quartz sand, 325 mesh quartz powder and 1250 mesh quartz powder, and it is recommended to abolish silica sand, crystal sand, glass sand and cast sand The names of sand making, white sand, super white sand, silica fume, silica fume, etc. are convenient to unify the industrial chain from mine to user with quartz, making the names simpler, easier to understand and unify.