Introduction
Silica is one of the most widely distributed materials in the earth’s crust, and quartz, a crystalline variety of silica, is predominantly composed of silicon dioxide (SiO2). However, the presence of certain impurities can alter its composition. Quartz is the most abundant mineral found on the earth’s surface.
Collectively described as silica minerals, quartz, quartz crystals, silica sand, and quartzite are all crystalline silicon dioxide with notable differences in their crystalline structures and trace impurities. Quartz has a wide range of applications, from gemstones and jewelry to glassmaking and electronic resonators. Much of the data presented here is sourced from reports by the Indian Bureau of Mines (IBM).
Quartz Varieties
- Crystalline or Macrocrystalline Varieties
- These varieties consist of crystals visible to the naked eye. Crystal quartz is widely used as a gemstone or for making jewelry. Although naturally colorless, quartz crystals can appear in various colors due to impurities.
- Key types include Aventurine, Amethyst, Eisenkiesel, vein quartz, milky quartz, ferruginous quartz, Cat’s eye, Rock crystal, transparent quartz, and Rose quartz. Massive crystalline quartz in the form of veins is found in almost all Indian states.
- Cryptocrystalline or Microcrystalline Varieties
- Grouped together by IBM, these varieties have tiny crystal grains visible only under an optical microscope.
- Examples include Chalcedony, agate, jasper, onyx, flint, and chert. These are prevalent in Gujarat, Uttar Pradesh, Tamil Nadu, Andhra Pradesh, Maharashtra, Madhya Pradesh, Karnataka, and Punjab. Notably, agate is abundant in Ratnapura, Rajpipla, and the region between the Tapi and Narmada rivers in Bharuch district, Gujarat.
- Clastic or Granular Varieties
- This group includes quartz sand, silica sand, sandstone, and quartzite.
- Silica sand contains at least 95% silica, primarily in the form of quartz. Industrial processing removes impurities to meet specific industry requirements, such as the glass industry, which requires almost 100% silica. Silica sand grains are finer than quartz sand grains. Quartzite is the rock form of silica sand.
Reserve and Resources
According to the NMI database, India’s total quartz and silica sand reserves/resources are estimated at 3,907.95 million tonnes. Of this, 647.53 million tonnes (17%) are in the reserved category, and 3,260.42 million tonnes (83%) are in the remaining resources category.
Resource grades:
- Foundry and molding grade: 735.59 million tonnes (19%)
- Glass grade: 649.77 million tonnes (17%)
- Ceramics and pottery grade: 438.44 million tonnes (11%)
- Ferrosilicon grade: 183.96 million tonnes (5%)
- Abrasive, sodium silicate, others, unclassified, and unknown: 1,900.18 million tonnes (48%)
Haryana alone accounts for about 1,653.65 million tonnes of these resources.
Production and Stock
Quartz, silica sand, and quartzite have been declared minor minerals by the Government of India since January 2015, and thus production, stocks, and prices post-2015 are unavailable on the IBM database.
- Quartz: In 2013-2014, India produced 1,395 thousand tonnes of quartz, with Andhra Pradesh being the largest producer.
- Silica Sand: In 2013-2014, production was 3,346 thousand tonnes, mainly from Gujarat, Rajasthan, Andhra Pradesh, West Bengal, and Tamil Nadu.
- Quartzite: In 2013-2014, production was 530,000 tonnes, primarily from Andhra Pradesh and Maharashtra.
Consumption
In 2015-2016, the consumption rate of quartz and silica sand was estimated at 2.79 million tonnes, with major consumers being:
- Glass industry: 41%
- Cement industry: 28%
- Ferro-alloys: 10%
- Iron and steel: 6%
- Foundry: 5%
- Fertilizer industry: 4%
Quartzite consumption was around 526 thousand tonnes, with the iron and steel industry consuming 67%, followed by ferroalloys (13%), refractory industry (10%), and sponge iron (9%).
Exports
India is a leading exporter of quartz, ranking second globally in 2017, exporting $61.5 million worth of quartz (13% of global exports). In 2015-2016, quartz exports were 301,366 tonnes (78% of total exports), while quartzite exports were 86,966 tonnes (22%).
Imports
In 2012-2013, India imported 1,652 tonnes of quartz and natural quartzite, mainly from Bangladesh (48%) and China (30%). Imports of silica sands significantly decreased to 54,379 tonnes from 129,490 tonnes the previous year, with major suppliers being Egypt (42%), Saudi Arabia (27%), and Italy (9%).
Conclusion
Quartz is a versatile mineral with extensive applications across various industries, including jewelry making, metal production, chemical production, construction, and recreation. Its unique properties make it valuable in foundry sand, abrasives, and the petroleum industry. This comprehensive overview, based on data from the Indian Bureau of Mines, highlights the significance of quartz in India’s industrial landscape.
References
This article draws on data from the Indian Bureau of Mines report on Quartz & Other Silica Minerals.
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