"gemstone ruby. The native inhabitants continued to assist the European explorers with their ruby exploration, leading them to some half dozen locations, spread out for over a hundred miles along the southwest shores of Greenland, known as the Kitaa Coast. Ruby and pink sapphire are the red and pink varieties of the mineral corundum, an aluminum-oxide mineral Al2O3. The pink/red colour is formed in corundum by adding the element chromium to its crystal structure. Spectroscopy of rubies from the Aappaluttoq occurrence in Greenland confirm the presence of chromium as well as showing absorption in the UV region indicating high Fe"
"oxygen. Corundum occurs as a mineral in mica schist, gneiss, and some marbles in metamorphic terranes. It also occurs in low silica igneous syenite and nepheline syenite intrusives. Other occurrences are as masses adjacent to ultramafic intrusives, associated with lamprophyre dikes and as large crystals in pegmatites. It commonly occurs as a detrital mineral in stream and beach sands because of its hardness and resistance to weathering. The largest documented single crystal of corundum measured about , and weighed . The record has since been surpassed by certain synthetic boules. Corundum for abrasives is mined in Zimbabwe, Pakistan, Afghanistan, Russia,"
"10.0 and moissanite falling somewhere in between corundum (ruby) and diamond in hardness. Sapphire, ruby, and pure corundum are α-alumina, the most stable form of AlO, in which 3 electrons leave each aluminum ion to join the regular octahedral group of six nearby O ions; in pure corundum this leaves all of the aluminum ions with a very stable configuration of no unpaired electrons or unfilled energy levels, and the crystal is perfectly colorless. When a chromium atom replaces an occasional aluminum atom, it too loses 3 electrons to become a chromium ion to maintain the charge balance of the"
"much lower values for both the hardness (7–20 GPa, which makes it softer than common oxides like corundum AlO and rutile TiO) and bulk modulus (~300 GPa). The oxides are commercially important ores of titanium. The metal can also be mined from other minerals such as ilmenite or leucoxene ores, or one of the purest forms, rutile beach sand. Star sapphires and rubies get their asterism from rutile impurities present in them. Titanium dioxide (B) is found as a mineral in magmatic rocks and hydrothermal veins, as well as weathering rims on perovskite. TiO also forms lamellae in other minerals."
"Chromium(III) oxide Chromium(III) oxide (or chromia) is the inorganic compound of the formula . It is one of the principal oxides of chromium and is used as a pigment. In nature, it occurs as the rare mineral eskolaite. adopts the corundum structure, consisting of a hexagonal close packed array of oxide anions with of the octahedral holes occupied by chromium. Similar to corundum, is a hard, brittle material (Mohs hardness 8 to 8.5). It is antiferromagnetic up to 307 K, the Néel temperature. It is not readily attacked by acids. occurs naturally in mineral eskolaite, which is found in chromium-rich"
"Hematite Hematite, also spelled as haematite, is the mineral form of iron(III) oxide (FeO), one of several iron oxides. It is the oldest known iron oxide mineral that has ever formed on earth, and is widespread in rocks and soils. Hematite crystallizes in the rhombohedral lattice system, and it has the same crystal structure as ilmenite and corundum. Hematite and ilmenite form a complete solid solution at temperatures above . Hematite is colored black to steel or silver-gray, brown to reddish brown, or red. It is mined as the main ore of iron. Varieties include ""kidney ore"", ""martite"" (pseudomorphs after"
"Columbite Columbite, also called niobite, niobite-tantalite and columbate [(Fe, Mn)NbO], is a black mineral group that is an ore of niobium. It has a submetallic luster and a high density and is a niobate of iron and manganese. This mineral group was first found in Haddam, Connecticut, in the United States. It forms a series with the tantalum-dominant analogue ferrotantalite and one with the manganese-dominant analogue manganocolumbite. The iron-rich member of the columbite group is ferrocolumbite. Some tin and tungsten may be present in the mineral. Yttrocolumbite is the yttrium-rich columbite with the formula (Y,U,Fe)(Nb,Ta)O. It is a radioactive mineral"
"Golden sheen sapphire Golden Sheen Sapphire, is a gemstone variety of the mineral corundum, an aluminium oxide (). It typically shows a metallic golden colour with common variations being brass, copper and bronze, however metallic blue, green and yellow colouration is also possible. A very rare variation is a metallic red colour. Unlike normal sapphire, golden sheen sapphire occurs principally as a result of iron and titanium inclusions, making the gem mostly opaque. In this respect, golden sheen sapphire is more like opal than other typically clear or transparent gemstone. Identified inclusions in golden sheen sapphire are ilmenite, rutile, hematite"
"typically soft, heavy, and brittle minerals. Oxide minerals are divided into three categories: simple oxides, hydroxides, and multiple oxides. Simple oxides are characterized by O as the main anion and primarily ionic bonding. They can be further subdivided by the ratio of oxygen to the cations. The periclase group consists of minerals with a 1:1 ratio. Oxides with a 2:1 ratio include cuprite (CuO) and water ice. Corundum group minerals have a 2:3 ratio, and includes minerals such as corundum (AlO), and hematite (FeO). Rutile group minerals have a ratio of 1:2; the eponymous species, rutile (TiO) is the chief"
"Titanium Titanium is a chemical element with symbol Ti and atomic number 22. It is a lustrous transition metal with a silver color, low density, and high strength. Titanium is resistant to corrosion in sea water, aqua regia, and chlorine. Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791, and was named by Martin Heinrich Klaproth after the Titans of Greek mythology. The element occurs within a number of mineral deposits, principally rutile and ilmenite, which are widely distributed in the Earth's crust and lithosphere, and it is found in almost all living things, water bodies, rocks,"
"he had in view, he produced a compound which is known as TUNGUM. Recognising that its close likeness to 22 carat gold would make it a marketable commodity the inventor carried out a series of tests which satisfied him that he had discovered a wonderful alloy."" The material is now mainly used in commercial diving and offshore applications, for the material's resistance to salt water corrosion. UNS C69100 UNS C69100, also known as Tungum alloy, CW700R and CZ127, is a bronze copper alloy. It has a naturally occurring oxide layer, which on exposure to reagents develops into a very thin"
"(turning it yellow or brown over time). Lanthanum oxide has replaced thorium dioxide in almost all modern high-index glasses. Thorium dioxide Thorium dioxide (ThO), also called thorium(IV) oxide, is a crystalline solid, often white or yellow in color. Also known as thoria, it is produced mainly as a by-product of lanthanide and uranium production. Thorianite is the name of the mineralogical form of thorium dioxide. It is moderately rare and crystallizes in an isometric system. The melting point of thorium oxide is 3300 °C – the highest of all known oxides. Only a few elements (including tungsten and carbon) and"
"for golden sheen sapphire. Testing of heat treatment on sample batches has resulted in diminishment of the gold sheen effect, reducing the appeal of the gemstone. The name 'golden sheen sapphire' is often shortened to 'gold sheen sapphire' and the name is interchangeable. Golden sheen sapphire has been used in jewelry production by companies including In 2016 a gold sheen sapphire ring by William Travis Jewelry won the American Gem Trade Association Savor Silver Award, Men's Wear. Golden sheen sapphire Golden Sheen Sapphire, is a gemstone variety of the mineral corundum, an aluminium oxide (). It typically shows a metallic"
"to yellow sapphire after oxidizing. After heating geuda to roughly 1800 °C, the aluminium oxide lattice-work of the gem is disrupted and cooling greatly improves both color and clarity. Though many stones are destroyed by the heating and cooling process, those that survive are significantly altered and rival naturally blue sapphires in both appearance and price. Geuda Geuda (, pronounced gay-yoo-dah) is a form of the mineral corundum, or sapphire, found primarily in Sri Lanka. Around 70%-80% of gems mined in Sri Lanka belong to geuda varieties. Because of its semitransparent and milky appearance due to rutile inclusions, these stones"
"Molybdenum Molybdenum is a chemical element with symbol Mo and atomic number 42. The name is from Neo-Latin ""molybdaenum"", from Ancient Greek "", meaning lead, since its ores were confused with lead ores. Molybdenum minerals have been known throughout history, but the element was discovered (in the sense of differentiating it as a new entity from the mineral salts of other metals) in 1778 by Carl Wilhelm Scheele. The metal was first isolated in 1781 by Peter Jacob Hjelm. Molybdenum does not occur naturally as a free metal on Earth; it is found only in various oxidation states in minerals."
"for high pressure systems (3,000 p.s.i.) and aluminium tubing for low pressure systems. Titanium Titanium is a chemical element with symbol Ti and atomic number 22. It is a lustrous transition metal with a silver color, low density, and high strength. Titanium is resistant to corrosion in sea water, aqua regia, and chlorine. Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791, and was named by Martin Heinrich Klaproth after the Titans of Greek mythology. The element occurs within a number of mineral deposits, principally rutile and ilmenite, which are widely distributed in the Earth's crust and"
"of Yogo sapphires claim that ""yogo"" may mean ""romance"" or ""blue sky"" in the Blackfoot language, although there is little evidence to support this claim. Other meanings for ""yogo"" have been suggested, including ""Going over the hill"". The meaning of the word ""Yogo"" had been lost by 1878, when placer gold was found in Yogo Creek. Thus, its true meaning is uncertain. Sapphires are a color variety of corundum, a crystalline form of aluminium oxide (). Corundum is one of the hardest minerals, rating 9 on the Mohs scale. Corundum gems of most colors are called sapphires, except for red"
"Thorium dioxide Thorium dioxide (ThO), also called thorium(IV) oxide, is a crystalline solid, often white or yellow in color. Also known as thoria, it is produced mainly as a by-product of lanthanide and uranium production. Thorianite is the name of the mineralogical form of thorium dioxide. It is moderately rare and crystallizes in an isometric system. The melting point of thorium oxide is 3300 °C – the highest of all known oxides. Only a few elements (including tungsten and carbon) and a few compounds (including tantalum carbide) have higher melting points. All thorium compounds are radioactive because there are no"
"Loellingite Loellingite, also spelled löllingite, is an iron arsenide mineral with formula FeAs. It is often found associated with arsenopyrite (FeAsS) from which it is hard to distinguish. Cobalt, nickel and sulfur substitute in the structure. The orthorhombic lollingite group includes the nickel iron arsenide rammelsbergite and the cobalt iron arsenide safflorite. Leucopyrite is an old synonym for loellingite. It forms opaque silvery white orthorhombic prismatic crystals often exhibiting crystal twinning. It also occurs in anhedral masses and tarnishes on exposure to air. It has a Mohs hardness of 5.5 to 6 and a quite high specific gravity of 7.1"
"Å and c = 13.58 Å at standard conditions. The unit cell contains six formula units. The lattice is analogous to that of corundum, with Cr replacing Al. Eskolaite Eskolaite is an uncommon chromium oxide mineral (chromium(III) oxide CrO). It was first described in 1958 for an occurrence in the Outokumpu ore deposit of eastern Finland. It occurs in chromium bearing tremolite skarns, metamorphosed quartzites and chlorite bearing veins in Finland; in glacial boulder clays in Ireland and in stream pebbles in the Merume River of Guyana. It has also been recognized as a rare component in chondrite meteorites. The"
"various oxidation states in minerals. Industrially, molybdenum compounds are used in high-pressure and high-temperature applications, as pigments and catalysts. Molybdenum minerals have long been known, but the element was ""discovered"" (in the sense of differentiating it as a new entity from the mineral salts of other metals) in 1778 by Carl Wilhelm Scheele. The metal was first isolated in 1781 by Peter Jacob Hjelm. Most molybdenum compounds have low solubility in water, but the molybdate ion MoO is soluble and forms when molybdenum-containing minerals are in contact with oxygen and water. Technetium is the chemical element with atomic number 43"
"constituents of oxides that make up the mineral. The bulk of the mineral is composed of Si and Al oxides, both adding up to about 60% of weight. Other oxides of Ca, Na, K and S are also present and make up the difference. A tiny fraction of a percent weight is also due to the presence of F and Cl. Trace amounts of Fe, Ti, Cr, Mg, Mn and Ba were also detected (<0.1 Oxide %). HO content was also calculated and FTIR spectroscopy confirmed only HO molecules and no hydroxide ions in the sample. A powdered sample of"
"clay, especially Armenian bole, have been used in gilding. Hematite is also used in art such as in the creation of intaglio engraved gems. Hematine is a synthetic material sold as ""magnetic hematite"". Hematite Hematite, also spelled as haematite, is the mineral form of iron(III) oxide (FeO), one of several iron oxides. It is the oldest known iron oxide mineral that has ever formed on earth, and is widespread in rocks and soils. Hematite crystallizes in the rhombohedral lattice system, and it has the same crystal structure as ilmenite and corundum. Hematite and ilmenite form a complete solid solution at"
"Kornerupine Kornerupine (also called ""Prismatine"") is a rare boro-silicate mineral with the formula (Mg,Fe)(Al,Fe)(SiO,BO)(O,OH). It crystallizes in the orthorhombic - dipyramidal crystal system as brown, green, yellow to colorless slender tourmaline like prisms or in massive fibrous forms. It has a Mohs hardness of 7 and a specific gravity of 3.3 to 3.34. Its indices of refraction are nα=1.660 - 1.671, nβ=1.673 - 1.683 and nγ=1.674 - 1.684. It occurs in boron-rich volcanic and sedimentary rocks which have undergone high grade metamorphism. It is also found in metamorphosed anorthosite complexes. Kornerupine is valued as a gemstone when it is found"
"actually corundum laced with trace elements (e.g., vanadium) or color-change spinel and are not actually chrysoberyl. As a result, they would be more accurately described as ""simulated alexandrite"" rather than “synthetic”. This alexandrite-like sapphire material has been around for almost 100 years and shows a characteristic purple-mauve colour change, which does not really look like alexandrite because there is never any green. Translucent yellowish chatoyant chrysoberyl is called cymophane or ""cat's eye"". Cymophane has its derivation also from the Greek words meaning 'wave' and 'appearance', in reference to the haziness that visually distorts what would normally be viewed as a"
"viewed via electron microscopy. The hexamolybdenum specimen was lost during an attempted ion probe analysis of a bordering grain. Other specimens can be found, however, in the Smithsonian Institution's National Museum of Natural History Allende section USNM 3509HC12 and in section USNM 7590 of NWA 1934, another VC3 chondrite. It has also been reported from the NWA 1934 CV3 carbonaceous chondrite meteorite from the Erfoud region of Morocco and in the Danubian placer of Straubing, Bavaria. Hexamolybdenum is an (molybdenum, ruthenium, iron, iridium, osmium) alloy. Color, streak, luster, hardness, tenacity, cleavage, fracture, density, and refractive index could not be observed"
"- ThO - UO. Small amounts of Fe and Zr also may be isomorphous with Th. Pb present is probably radiogenic. Usually found in alluvial deposits, beach sands heavy mineral placers and pegmatites. Thorianite Thorianite is a rare thorium oxide mineral, ThO. It was originally described by Ananda Coomaraswamy in 1904 as uraninite, but recognized as a new species by Wyndham R. Dunstan. It was so named on account of its high percentage of thorium; it also contains the oxides of uranium, lanthanum, cerium, praseodymium and neodymium. Helium is present, and the mineral is slightly less radioactive than pitchblende, but"
"Strontium Strontium is the chemical element with symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to air. Strontium has physical and chemical properties similar to those of its two vertical neighbors in the periodic table, calcium and barium. It occurs naturally mainly in the minerals celestine and strontianite, and is mostly mined from these. While natural strontium is stable, the synthetic Sr isotope is radioactive and is one of the most dangerous components of"
"small size of the difference in density and difficulties in measuring it accurately, but, with increased accuracy in factors used for calculating density X-ray crystallographic data yielded densities of 22.56 g/cm for iridium and 22.59 g/cm for osmium. Iridium is the most corrosion-resistant metal known: it is not attacked by almost any acid, aqua regia, molten metals, or silicates at high temperatures. It can, however, be attacked by some molten salts, such as sodium cyanide and potassium cyanide, as well as oxygen and the halogens (particularly fluorine) at higher temperatures. Iridium forms compounds in oxidation states between −3 and +9;"
"Limonite Limonite () is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO(OH)·HO, although this is not entirely accurate as the ratio of oxide to hydroxide can vary quite widely. Limonite is one of the three principal iron ores, the others being hematite and magnetite, and has been mined for the production of iron since at least 2500 BCE. Limonite is named for the Greek word (/leː.mɔ̌ːn/), meaning ""wet meadow"", or (/lím.nɛː/), meaning “marshy lake” as an allusion to its occurrence as bog iron ore in meadows"
"within a 60-70 Rockwell hardness C range which is comparable only to hardened carbon steel alloys, but considerably inferior to the hardness of natural and synthetic corundum. Instead, with plasma electrolytic oxidation, the coating is porous only on the surface oxide layer while the lower oxide layers are much more compact than with standard DC anodizing procedures and present a higher crystallinity due to the oxide layers being remelted and densified to obtain α-Al2O3 clusters with much higher coating hardness values circa 2000 Vickers hardness. Alumina is used to manufacture tiles which are attached inside pulverized fuel lines and flue"
"glassmaking and also as a glaze for ceramics. Green chromium oxide is extremely lightfast and as such is used in cladding coatings. It is also the main ingredient in infrared reflecting paints, used by the armed forces to paint vehicles and to give them the same infrared reflectance as green leaves. Natural rubies are corundum (aluminum oxide) crystals that are colored red (the rarest type) due to chromium (III) ions (other colors of corundum gems are termed sapphires). A red-colored artificial ruby may also be achieved by doping chromium(III) into artificial corundum crystals, thus making chromium a requirement for making"
"Noble metal In chemistry, the noble metals are metals that are resistant to corrosion and oxidation in moist air (unlike most base metals). The short list of chemically noble metals (those elements upon which almost all chemists agree) comprises ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), osmium (Os), iridium (Ir), platinum (Pt), and gold (Au). More inclusive lists include one or more of mercury (Hg), rhenium (Re) and copper (Cu) as noble metals. On the other hand, titanium (Ti), niobium (Nb), and tantalum (Ta) are not included as noble metals although they are very resistant to corrosion. While the"