gemstones Description of minerals new.pptx

about gemstones an extraction about minerals

1. STUDY OF PRECIOUS AND SEMI PRECIOUS STONES SYSTEMATIC DESCRIPTION, GENESIS, MODE OF OCCURRENCE, DISTRIBUTION IN INDIA, AND IMPORTANT WORLD OCCURRENCES Precious Gemstones: Diamond, Ruby, Sapphire, and Emerald

2. Diamond Diamond ore  is a rare, naturally occurring mineral composed of carbon that generates deep underground. Each carbon atom in a diamond is surrounded by four other carbon atoms and connected to them by strong covalent bonds - the strongest type of chemical bond. Diamond is the hardest known natural substance. It is also chemically resistant and has the highest thermal conductivity of any natural material. These properties make it suitable for use as a cutting tool and for other uses where durability is required.

3. Diamond Chemical Composition : C   Diagnostic Characters : Colour – Colorless, or white, sometimes yellow, red, green or very rarely blue or black Form – Octahedral crystal, having curved faces, commonly twinned. Crystal System – Cubic Hardness – 10 Sp. gravity – 3.47 to 3.56 Streak – Colorless Lusture – Brilliantly admantine Cleavage – Perfect (111) Fracture – Irregular/uneven

4. Genesis of Diamond Most Gem quality diamonds come from the depth of 150 to 200 Km from the surface of the Earth. Those part ( section ) of the earth have very high tempreture and pressure which allow the formation of Diamond. Diamond form in mantle through magmatic processes. It includes magma generation, crystallization, and hydrothermal activity which play a crucial role in the formation of ore deposits, concentrating valuable minerals through processes like segregation (to seperate) , crystallization, and the transport of metals in magmatic fluids. During the ascend of a hot melt, certain minerals crystallise when pressure and temperature decreases, and specific mineral species become stabl e. Very rapid transport of Kimberlite ( a rare, blue-tinged, coarse-grained intrusive igneous rock sometimes containing diamonds, found in South Africa and Siberia ) magma creating an upward path by hydraulic fracturing of earth crust and forming volcanic pipe structure.

5. Mode of occurrence of Diamond Diamonds occur in the Kimberlite pipes of the igneous rocks. Diamonds also found along ancient and existing shorelines known as placer diamond. It tends to accumulate because its size and high density Placer types of diamond deposits were derived from localized igneous rocks through weathering, erosion and traportation by river or water current.

6. Diamond Uses of Diamond: It is the most valued gemstone. They are used in jewellery because of their durability and lustre property Used for industrial purpose. Its property of hardness is useful to drill, grind or cut materials. Diamond bits are used for drilling holes. They are present on the edges and tips in small sizes. In beauty products is to reduce wrinkles etc. To improve sound quality it is used in audio equipment. Nanodiamonds have potential health benefits.

7. Diamond Indian distribution: Diamond deposits in India occur in three types of geological settings Kimberlite pipes Conglomerate beds Alluvial gravels   The main diamond bearing areas are: Andhra Pradesh – Wajrakrur of Anantpur district ( kimberlite pipes), Karnool , ( Ramallakota-Banganapalli Conglomerate of Lower Vindhyan ), Cuddapah districts and Krishna river basin (gravel deposits) M.P . – Panna belts (Conglomerates separating different formations of Upper Vindhyan , kimberlite pipes and gravel beds) Biha r and Jharkhand – Palamu and Ranchi ( Sankh river) distrctsare also reported. Stray occurrences are also recorded in localized area of U.P., Orissa and Maharashtra.

8. Diamond World distribution: Major producing countries include Russia, Botswana, Canada, the Democratic Republic of the Congo, and South Africa , Australia , Zimbabwe and Angola . Worldwide reserves of diamonds are estimated at 1.7 billion carats. Russia has the largest diamond reserves in the world, estimated at some 860 million carats.

9. Corundum (Ruby, Blue Sapphire ) ChemicalComposition : Al 2 O 3 Red corundums are known as " rubies, " produced by the presence of chromium in the gem. A small trace of chromium will produce a pink color. To be considered a ruby, there must be enough chromium to give the gem a distinctly red color.   Blue corundums are known as " sapphires” . Trace amounts of iron and titanium can produce a blue color in corundum.

10. Gem-quality corundum also occurs in a wide range of other colors, including pink, purple, orange, yellow, and green. These gems are known as " fancy sapphires. ”

11. Ruby : Rubies must have a combination of color and clarity that makes them an attractive gem. Heating corundum crystals under controlled conditions can improve or intensify their color. Heating can also remove inclusions by causing them to dissolve, making them less visible and improving the clarity of a gem. A more permanent type of fracture treatment is to fill the fractures with minor amounts of flux, glass, or another durable material. These enter the fractures during the heat treatment process. When the stone cools, a permanent filling of the fracture was accomplished.

12. Sapphire: The name "sapphire" is used for corundums that range from a very light blue to a very dark blue color. The blue can range from a greenish blue to violetish blue. Gems with a rich blue to violetish blue color are the most desirable. Sapphires are also subjected to a wide variety of heat and fracture-filling treatments. Sri Lanka, India, Myanmar, Thailand, and Australia have historically been important sources of fancy sapphire. Minor amounts have been produced in numerous other countries. Africa has become an important source of fancy sapphires. Deposits in Tanzania, Kenya, Madagascar, Ethiopia, Nigeria, and other countries are producing these colorful gems

13. Corundum (Ruby, Blue Sapphire ) ChemicalComposition : Al 2 O 3   Diagnostic Characters: Color – usually grey, also greenish, reddish, dull white, sometimes colorless Form – Mostly barrel shaped or pyramidal crystal, also massive and granular Crystal System – Hexagonal Hardness – 9 Sp. gravity – 4 Streak – colorless Lusture – Vitreous Cleavage – Absent Fracture – Uneven/ concoidal  

14. Genesis of Corundum (Ruby, Blue Sapphire ) Ruby / Blue Sapphire formation occurs through a process called crystallization, in which minerals are transformed from a molten state into a solid crystalline form. During this process, the necessary elements like aluminum and oxygen come together to form corundum crystals, which can then become ruby if they contain enough chromium to give them a red color. The specific conditions required for ruby / Blue Sapphire formation include high temperature and pressure, as well as the presence of certain chemical elements like aluminum, oxygen, and chromium. The process of ruby formation can take millions of years and usually occurs in locations where these conditions are met, such as in areas with high geothermal activity or where tectonic plates are colliding. The mineral Corundum are formed/originated in the metamorphic rocks (schist and gneiss) and ignious rocks (basalt) under very high temprature and pressure condition. It is also found in sedimentary rocks with heavy minerls and black sands.

15. Mode of occurrence of Corundum (Ruby, Blue Sapphire ) Corundum occurs as mineral metamorphosed clayey rocks and limestones (mica-schist, gneiss and some marbles). It also occurs in Igneous rocks (syanite and nepheline syanite). Other occurrences are masses adjacent to ultramafic intrusives associated with lamprophyre dykes and as large crystals in pegmetites. It occurs in alluvial deposits as rounded pebbles. It commonly occurs as detrital minerals in stream and beach sands because of its hardness and specific gravity.

16. Corundum (Ruby, Blue Sapphire ) Uses of Corundum : As an Aabrasive As a gemstone – coloured varieties e.g. ruby and sapphire.   Indian distribution : The important regions are: A.P . – Khammam district Assam – Sonapahar Jharkhand – Singhbhum district M.P. – Sidhi ( Rewa , Pipra ) and Bastar districts Maharashtra – Bhandara district Karnataka – Hassan, Bellary, Tumkur , Bangalore, Mysore and Chikmagalur district Rajasthan – Tonk district T.N. - Coimbatore in Sivamalai Hills ( syenite ). Also known from Meghalaya

17. Corundum (Ruby, Blue Sapphire ) World Distribution: The most significant ruby deposits are found in Asia, particularly in Myanmar (Burma), which is known for producing some of the finest rubies in the world. Other significant ruby deposits are found in regions of Sri Lanka, Thailand, Vietnam, and Cambodia . In Africa, significant ruby deposits have been found in Madagascar, Mozambique, and Tanzania . In these locations, rubies are typically found in metamorphic rocks such as marble, gneiss, and schist. Ruby deposits have also been discovered in other parts of the world, such as in the United States (North Carolina), Greenland, Afghanistan, Pakistan, and Australia.

18. Topaz ( Yellow Sapphire/ Pukhraj ) The yellow sapphire gemstone is considered to be extremely precious. It’s the twin of blue sapphire. The amplitude of metaphysical properties ( beyond the scope of physical observation and scientific explanation, often relating to spiritual or energetic aspects ) of this Jupiter (Guru) stone possesses are powerful. As the name suggests, yellow sapphire comes in yellow, orange and golden colors. The source of this color is iron and titanium. Yellow sapphires have been used in jewelry for centuries. In fact, the ancient Greeks and Romans believed that the yellow sapphire had the power to protect its wearer from evil spirits. In metaphysical contexts, yellow sapphire, or Pukhraj, is believed to   enhance wisdom, prosperity, and happiness, acting as a "wisdom stone" and a symbol of spiritual growth, intellectual clarity, and attracting good fortune.

19. Topaz ( Yellow Sapphire/ Pukhraj ) Yellow sapphires, also known as Pukhraj stones, are gemstones of the corundum family of minerals. Pukhraj stones are renowned for their vibrant yellow hues and exceptional brilliance; these gemstones, often confused with Topaz, Topaz is a similar-looking, but much cheaper version of yellow sapphire, this gemstone is easily available and doesn't cost much. On the Mohs scale, the hardness of topaz is 8.0 which is less than the Yellow Sapphire. It is a semi-precious gemstone that is found in abundance and so is not much expensive. Yellow Sapphire is a rigid stone. The stone is extensively hard and the hardness of the stone measures 9.0 on the moh scale. Yellow sapphires have been used in jewelry for centuries. In fact, the ancient Greeks and Romans believed that the yellow sapphire had the power to protect its wearer from evil spirits.

20. Corundum ChemicalComposition : Al 2 O 3   Diagnostic Characters: Color – usually grey, also greenish, reddish, dull white, sometimes colorless Form – Mostly barrel shaped or pyramidal crystal, also massive and granular Crystal System – Hexagonal Hardness – 9 Sp. gravity – 4 Streak – colorless Lusture – Vitreous Cleavage – Absent Fracture – Uneven/ concoidal  

21. Topaz ( Yellow Sapphire/ Pukhraj ) Chemical Composition: Al 2 Si 4 (F,OH) 2   Diagnostic Characters: Color – Colorless or wine yellow Form – Prismatic, also massive or granular Crystal System – Orthorhombic Hardness – 8 Sp. gravity – 3.5-6 Streak – Colorless or white Lusture – Vitreous Cleavage – Perfect parallel to base Fracture – Subconcoidal to uneven

22. Genesis of Topaz ( Yellow Sapphire/ Pukhraj ) Yellow topaz, a gemstone with a vibrant yellow hue, is formed during the final stages of igneous rock formation under intense pressure and temperature, typically in granitic pegmatites or vapor cavities in rhyolite lava flows. Topaz usually forms along fractures and in cavities of igneous rocks like rhyolite, granite or pegmatite. The crystals grow in the late stages of a magma cooling, when there is enough fluorine to enable the formation of topaz Yellow sapphire , a member of the corundum mineral family, forms through the crystallization of aluminum oxide (Al ₂ O ₃ ) with trace amounts of iron, while topaz , a silicate mineral, forms from aluminum and fluorine, often in igneous rocks.

23. Mode of occurrence of Topaz ( Yellow Sapphire/ Pukhraj ) Topaz is found in a variety of geological settings around the world, often associated with certain types of rocks and minerals. It commonly occur in cavities and fractures of felsic igneous rocks like granite, pegmatite, and rhyolite, often associated with hydrothermal fluids rich in fluorine. Igneous Rocks: Topaz is commonly associated with igneous rocks, specifically those rich in silica and fluorine, such as granites, rhyolites, and pegmatites. Pegmatites: Pegmatites, which are coarse-grained igneous rocks, often contain topaz crystals, especially in their cavities. Rhyolite Lava Flows: Topaz can also be found in vapor cavities within rhyolite lava flows. Hydrothermal Veins: Topaz can also occur in high-temperature veins. Alluvial Sediments: Topaz can also be found in alluvial sediments after weathering out of its host rock.

24. Topaz ( Yellow Sapphire/ Pukhraj ) Indian Distribution: Singhbhum (Jharkhand), Bhandara (Maharashtra), Degana Mine in Nagaur District and Sirohi ( Rajsthan ), Kodarma Mica Belt (Jharkhand & Bihar ) World Distribution: Topaz is found in various locations of the world: Ural and Ilmensky mountains of Russia, Afghanistan, Sri Lanka, Czech Republic, Germany, Norway, Pakistan, Italy, Sweden, Japan, Brazil, Mexico, Flinders Island (Australia), Nigeria, Ukraine, and the United States.

25. Emerald ( Beryl ) Emerald (Panna) is a gemstone which is a deep green or pale green variety of the mineral beryl due to presence of trace amounts of chromium or sometimes vanadium . E meralds with unique smooth green colour with high degree of transparency are considered as most precious among gemstones. To be an emerald, a specimen must have a distinctly green color that falls in the range from bluish green to green to slightly yellowish green . ( The cut stones are known as gems, while uncut - ones are gemstones. ) Emeralds are rare and precious gemstones that command immense value on account of their cut, colour, clarity and carat . ( Beauty, rarity and durability are the main virtues of a gemstone. ) It benefits those who are afflicted with lung illnesses, skin conditions, allergies, or skin conditions .

26. Emerald ( Beryl )   Chemical Composition : Be 3 Al 2 Si 6 O 18   Diagnostic Characters : Colour –Commonly pale green, blue, yellow, white Form – Crystal common (hexagonal form), also massive Crystal System – Hexagonal Hardness – 7.5 to 8 Sp. gravity – 2.7 Streak – white Lusture – Vitreous Cleavage – concoidal or uneven Fracture – indistinct

27. Genesis of Emerald ( Beryl ) Emeralds, a variety of the mineral beryl,   formed in geological environments where specific elements and conditions converge. It takes over millions of years in hydrothermal veins where hot, mineral-rich fluids interact with the Earth's crust, depositing beryl crystals, and the green color comes from chromium, vanadium, and iron impurities.  It typically forms in hydrothermal veins where hot, mineral-rich fluids circulate through cracks in the Earth's crust. These fluids interact with the surrounding rocks, depositing beryl crystals over time. The green color of emeralds is due to the presence of trace amounts of chromium, vanadium, and iron. Emeralds also form in contact metamorphic rocks where magma comes into contact with sedimentary rocks like limestone or shale. It requires the presence of beryllium, aluminum, silicon, oxygen, and trace amounts of chromium or vanadium for its characteristic green color. Emeralds typically form in igneous and metamorphic rocks, often associated with pegmatites and hydrothermal veins.

28. Genesis of Emerald ( Beryl ) Specific temperature and pressure conditions are necessary for emerald formation. Emeralds typically form within a temperature range of 400 ° C to 700 ° C (750 ° F to 1300 ° F) and under moderate pressure. These conditions are found in metamorphic and igneous environments where hydrothermal fluids rich in beryllium, chromium, and vanadium transport and deposit these elements into host rocks. The geological formation of emeralds happens in two primary environments: Magmatic-Hydrothermal Deposits: Emeralds form when hydrothermal fluids interact with magmatic rocks, such as granites, which supply beryllium. Chromium or vanadium, sourced from ultramafic rocks, adds the green color. Metamorphic-Hydrothermal Deposits : These deposits occur in tectonic settings where hydrothermal fluids mix with metamorphic rocks rich in chromium or vanadium, creating the perfect environment for emerald crystallization. Millions of years of geological processes are required for emeralds to develop to a significant size and quality .

29. Mode of occurrence of Emerald ( Beryl ) Emeralds are found within host rocks that provide the necessary geological conditions for their formation. Key host rocks include: Pegmatites : These magmatic (igneous) rocks are rich in beryllium, essential for forming beryl. Mica- Schist: A metamorphic rock often associated with chromium or vanadium, providing the coloring agents for emeralds. Black Shale: Found in Colombian deposits, this rock is rich in organic materials and chromium, creating emeralds with unique qualities. Hydrothermal Veins: These are veins filled with superheated water that can transport and deposit the necessary elements for emerald formation.

30. Indian distribution of Emerald ( Beryl ) The important regions are: Andhra Pradesh & Telangana – Nellore, Srikakulam and Visakhapatnam districts . Bihar & Jharkhand – Hazaribagh , Giridih,Monghyr , gaya and Ranchi. Rajasthan – Mewar , Ajmer, Bhiwara , Sikar and Udaipur Pegmetite belt. It has also been reported from A.P., Assam, J & K, Karnakata , Kerala, M.P., Orissa, T.N. and West Bengal but hardly of economic importance.

31. Worldwide distribution of Emerald ( Beryl ) Emerald deposits are rare and found in specific regions where geological conditions align perfectly: Colombia: The most famous source of emeralds, Colombia produces stones renowned for their vivid green color and exceptional clarity. Key mining areas include Muzo, Chivor, and Coscuez. Zambia: Emeralds from Zambia are known for their deep green hue with a touch of bluish tones, primarily mined in the Kagem region. Brazil: Brazil produces emeralds in a variety of green shades, often with a bluish tint, from regions like Bahia and Minas Gerais. Afghanistan: The Panjshir Valley yields high-quality emeralds with stunning transparency and intense color. Russia: The Ural Mountains have long been a source of emeralds, characterized by their bright green hues.

32. Aquamarine (Pale blue variety of Beryl) Aquamarine is a fairly common  gemstone . It is named after the color of sea water. It is the blue, pale-blue to light-green variety of the  beryl family .  It's known for its clear, often transparent appearance and its colour which is typically a soft, calming blue, sometimes with hints of green. Aquamarine was first discovered in modernity far from the sea in Siberia in 1723. It is transparent to translucent and possesses a hexagonal crystal system. Aquamarine receives its color from the presence of two different types of iron: ferrous and ferric. Ferrous iron provides the gem with its trademark blue color , whilst the presence of ferric iron turns the gem slightly green. The colour of aquamarine can also be changed by heat, with a goal to enhance its physical appearance It is also known as “ Jalmani ” and associated with the planet Saturn (Shani grah ) [Aquamarine stone is believed to be associated with calming, communication, and emotional healing, while some believe it can also aid with throat and respiratory issues.]

33. Aquamarine (Pale blue variety of Beryl) Why is Aquamarine, Blue? Aquamarine is blue by definition, with the color ranging from the lightest pastel blue to the signature “Aquamarine” color that has the tiniest bit of green in it, to something a bit darker . Since blue color is a defining property of Aquamarine, it doesn't come in any other color . Gemologists have determined that the blue color is a result of iron in the crystal, with the shade of blue being determined by the way in which the iron was incorporated.

34. Aquamarine (Beryl)   Chemical Composition : Be 3 Al 2 Si 6 O 18   Diagnostic Characters : Colour –Commonly pale green, blue, yellow, white Form – Crystal common (hexagonal form), also massive Crystal System – Hexagonal Hardness – 7.5 to 8 Sp. gravity – 2.7 Streak – white Lusture – Vitreous Cleavage –absent or uneven Fracture – indistinct

35. Genesis of Aquamarine Like most minerals, Aquamarine forms deep inside the earth. Unlike some minerals, this precious gem forms in a variety of rock, including both igneous and metamorphic rock. As a source of beryllium, the mineral beryl is fairly rare.  Aquamarine mainly forms in granite pegmatites (coarse-grained igneous rock) and hydrothermal vents, and it is a very lengthy process that can take millions of years to form. Aquamarine may also be formed by  hydrothermal fluids , which are hot, mineral-rich solutions. These liquids contain dissolved minerals and metals as they move through fissures and cavities in the crust of the Earth.

36. Occurrence of Aquamarine Aquamarine can mostly be found in granite pegmatites.  It can also be found in veins of metamorphic rocks that became mineralized by hydrothermal activity. Its occurrences have been reported in pegmatites intruding Archaean schists and gneisses. Uses of Aquamarine Although aquamarine is mainly used for jewellery, aquamarine powder has proven to be a beneficial ingredient in cosmetics. It has a binding and skin protecting function that ensures protection of the skin from external influences.

37. Indian distribution of Aquamarine Andhra Pradesh:  Aquamarine has been reported from Vemireddipalle in the Krishna District, Andhra Pradesh.  Odisha:  Aquamarine has been found in pegmatites in the state, particularly in Sambalpur, Sabarnapur , and Bolangir districts .   Rajasthan:  Aquamarine is reported from the Aravalli region.  Tamil Nadu:  Aquamarine is found in pegmatites in the Karur- Kangayam region of Tiruchurapalli district and Salem district.  Karnataka:  Aquamarine has been reported from Melukote in Hassan district and pegmatites intruding Archaean schists and gneisses.  Kerala:  Aquamarine has also been reported from Kerala. 

38. World distribution of Aquamarine Aquamarine gemstone is mined mainly in Brazil, but it is also found in Nigeria, Madagascar, Zambia, Pakistan, Mozambique, Afghanistan ,  China ,  Kenya ,  Russia ,  the  United States ,  Brazil , ,  Tanzania ,  Sri Lanka , Malawi ,  India , Zimbabwe ,  Australia ,  Myanmar , and  Namibia . Today, the main deposits are in Pakistan (high in the mountains) and Brazil. Most of the mining is either done by picking through surface deposits or by strip mining.

39. CORAL (Munga)