Minerals are natural solid substances with a specific chemical composition and ordered atomic arrangement, distinguishable by their distinct luster, streak, hardness, color or magnetism.
Plate tectonics provided Earth with a diverse collection of minerals through repeated melting and resolidifying of rocks, which created new crust while devouring old. Repeated melting and resolidifying also concentrated unusual elements into exotic minerals that make up its crust.
1. Quartz
Quartz is an abundant and widely-spread mineral. The transparent crystals containing silicon dioxide were historically employed as beads and talismans by ancient cultures, particularly Greeks who thought of quartz as fossilized ice, giving rise to their name for this mineral: “krystallos,” meaning “ice”.
Quartz is a hard, durable material with excellent corrosion-resistance that’s the second-most abundant crystalline material on Earth, second only to diamond. Although most quartz minerals are white in hue, impurities in its atomic lattice can produce various colors of this mineral; amethyst being most famous as it often features beads-of-needle inclusions; other notable quartz gemstones include citrine with yellow to orange shades as well as alexandrite with its color changing capabilities that range from green blue hues back red!
Quartz can form sandstone, such as that found along Lake Superior’s gravel beaches. Silica sand is widely used as an abrasive and in the production of glass, ceramics and foundry molds for metal casting, while quartz-based glasses can be found in various optical devices and electronic sensors.
2. Garnet
Garnets come in various shades. Red garnets (pyrope, rhodolite and almandine) are perhaps best known as gemstones and often serve as symbolic reminders of endurance, strength and friendship. Furthermore, their hue can provide geologists with information about the metamorphic grade of their host rocks.
Garnets form when sedimentary rocks with high aluminum contents undergo metamorphism and metamorphic conditions heat and pressurize the garnets into recrystallizing again under heat and pressure; their composition and chemical makeup often reflect their unique conditions of origin.
Almandine typically forms from regional metamorphism of clay sediments, while pyrope occurs in silica-rich igneous rocks with spessartine typically found associated with granite pegmatites. Grossular and andradite typically form from metamorphosed carbonate rocks while uvarovite can be found in chrome-rich metamorphic rock. At mineral processing plants, garnet is separated from heavier gangue minerals by washing and sometimes flotation before being further graded into size classes to meet specific market demands.
3. Pyrite
Pyrite is an incredible mineral, popularly referred to as “Fool’s Gold.” With its brilliant metallic luster and brassy to golden hue, pyrite stands out among rocks. Due to its similarity with real gold, many non-experts mistake it for this precious metal; however it is much harder than gold and typically forms into cubes or multifaceted crystals with well-defined flat faces that give rise to its nickname of Fool’s Gold.
Pyrite jewelry boasts stunning beauty as well as durability; Mohs Hardness Scale rating 6 makes pyrite hard enough for regular wear with confidence.
Pyrite can be found in many geological formations, as an accessory mineral in igneous rocks, hydrothermal veins, coal beds and even as part of the makeup of nutritional supplements, ink cartridges, lawn conditioners and water treatments as well as being an effective moss killer. Pyrite also plays an integral part in producing iron sulfate used to manufacture various products including nutritional supplements, ink cartridges, lawn conditioners and water treatments as well as being utilized as an ingredient in antimicrobial moss killer.
4. Sulfur
Sulfur, known for its mythic associations in myths and legends, is the tenth-most abundant element in our universe and has its own distinct smell. Sulfur can be found combined with other elements or metals in several minerals including lead sulfide (PbS), blende (zinc sulfide, ZnS), pyrite (iron sulfide FeS2) and mercury sulfide (HgS) along with several sulfate minerals such as calcium sulfate CaSO42), potassium aluminium Sulfate KSO4) and celestite (sodium Sulfate NaSO4).
Organic sulfur compounds are vitally important to living organisms. Organisms need organosulfur compounds like those responsible for intestinal gas odors and antibiotic cysteine to function optimally, while terrestrial ecosystems rely on sulfates as the natural source of sulfur for plants and microorganisms, with atmospheric deposition and weathering contributing the majority of sulfur to terrestrial environments. Sulfur with different isotopic composition can be used to identify pollution sources while additional sources can help boost plant uptake of other essential nutrients.
