"then placed under the imitation stone. Trade terms such as balas ruby for red spinel and rubellite for red tourmaline can mislead unsuspecting buyers. Such terms are therefore discouraged from use by many gemological associations such as the Laboratory Manual Harmonisation Committee (LMHC). Ruby A ruby is a pink to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide). Other varieties of gem-quality corundum are called sapphires. Ruby is one of the traditional cardinal gems, together with amethyst, sapphire, emerald, and diamond. The word ""ruby"" comes from ""ruber"", Latin for red. The color of a ruby is due"
"other rubies of similar quality. After color follows clarity: similar to diamonds, a clear stone will command a premium, but a ruby without any needle-like rutile inclusions may indicate that the stone has been treated. Ruby is the traditional birthstone for July and is usually more pink than garnet, although some rhodolite garnets have a similar pinkish hue to most rubies. The world's most valuable ruby is the Sunrise Ruby. Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness. Among the natural gems only moissanite and diamond are harder, with diamond having a Mohs hardness of"
"Sapphirine Sapphirine is a rare mineral, a silicate of magnesium and aluminium with the chemical formula (Mg,Al)(Al,Si)O (with iron as a major impurity). Named for its sapphire-like colour, sapphirine is primarily of interest to researchers and collectors: well-formed crystals are treasured and occasionally cut into gemstones. Sapphirine has also been synthesized for experimental purposes via a hydrothermal process. Typical colours range from light to dark sapphire blue, bluish to brownish green, green, and bluish or greenish gray to black; less common colours include yellow, pale red, and pink to purplish pink. Sapphirine is relatively hard (7.5 on Mohs scale), usually"
"Sunrise Ruby The Sunrise Ruby is the world's most expensive ruby, most expensive coloured gemstone, and most expensive gemstone other than a diamond. Originally mined in Myanmar, Its current name is named after a poem of the same name, written by the 13th-century Sufi poet Rumi. It is a Burmese ""pigeon blood"" ruby mounted by Cartier and set between heptagonal diamonds weighing and . It is considered among the rarest of all gemstones. The Swiss Gemmological Institute has described it as ""a unique treasure of nature"" and praised its ""well-proportioned cut, highly attractive colour and fine purity"". The Gubelin Gem"
"(""proper"", ""unalterable"", ""unbreakable"") and sometimes called adamant, diamond is the hardest known naturally occurring material, scoring 10 on the Mohs scale of mineral hardness. Diamond is extremely strong owing to the structure of its carbon atoms, where each carbon atom has four neighbors joined to it with covalent bonds. The material boron nitride, when in a form structurally identical to diamond (zincblende structure), is nearly as hard as diamond; a currently hypothetical material, beta carbon nitride, may also be as hard or harder in one form. It has been shown that some diamond aggregates having nanometer grain size are harder"
"from tiny pieces of natural gems. Watches often had garnet, quartz, or even glass jewels; only top quality watches used sapphire, ruby, or diamond. In 1902, a process to grow artificial sapphire crystals was invented, making jewels much cheaper. Jewels in modern watches are all synthetic sapphire or (usually) ruby, made of corundum (AlO), one of the hardest substances known. The only difference between sapphire and ruby is that different impurities have been added to change the color; there is no difference in their properties as a bearing. The advantage of using jewels is that their ultrahard slick surface has"
"only in ruby. Sapphire and ruby are both varieties of the same mineral; corundum. Some minerals may replace other existing minerals while preserving the original's habit: this process is called pseudomorphous replacement. A classic example is tiger's eye quartz, crocidolite asbestos replaced by silica. While quartz typically forms ""prismatic"" (elongate, prism-like) crystals, in tiger's eye the original ""fibrous"" habit of crocidolite is preserved. The names of crystal habits are derived from: Predominant crystal faces (prism – prismatic, pyramid – pyramidal and pinacoid – platy). Crystal forms (cubic, octahedral, dodecahedral). Aggregation of crystals or aggregates (fibrous, botryoidal, radiating, massive). Crystal appearance"
"very hard, transparent crystals in a variety of colors. It is naturally amber-colored, but becomes colorless after exposure to sunlight. Topaz forms within cavities of the volcanic rock rhyolite, from eruptions that occurred during the Tertiary Period six to seven million years ago. Topaz is embedded in the rhyolite rock, and also found loose on the slopes and arroyos. Red beryl, a rare mineral found at Topaz Mountain, occurs as small crystals, often attached to other mineral crystals. It is estimated that one red beryl crystal is found for every 150,000 diamonds. Prices for top quality natural red beryl can"
"Topaz Topaz is a silicate mineral of aluminium and fluorine with the chemical formula AlSiO(F, OH). Topaz crystallizes in the orthorhombic system, and its crystals are mostly prismatic terminated by pyramidal and other faces. It is one of the hardest naturally occurring minerals (Mohs hardness of 8) and is the hardest of any silicate mineral. This hardness combined with its usual transparency and variety of colors means that it has acquired wide use in jewellery as a cut gemstone as well as for intaglios and other gemstone carvings. Topaz in its natural state is a golden brown to yellow, a"
"Emerald Emerald is a gemstone and a variety of the mineral beryl (BeAl(SiO)) colored green by trace amounts of chromium and sometimes vanadium. Beryl has a hardness of 7.5–8 on the Mohs scale. Most emeralds are highly included, so their toughness (resistance to breakage) is classified as generally poor. Emerald is a cyclosilicate. The word ""emerald"" is derived (via and ), from Vulgar Latin: ""esmaralda""/""esmaraldus"", a variant of Latin ""smaragdus"", which originated in (smaragdos; ""green gem""). Emeralds, like all colored gemstones, are graded using four basic parameters–the four ""C""s of connoisseurship: ""color"", ""clarity,"" ""cut"" and ""carat weight"". Normally, in the"
"Dome Rock Mountains of La Paz County, Arizona, Stockdale, Riley County, Kansas; Cortlandt, New York; and Clay County, North Carolina. Sapphirine Sapphirine is a rare mineral, a silicate of magnesium and aluminium with the chemical formula (Mg,Al)(Al,Si)O (with iron as a major impurity). Named for its sapphire-like colour, sapphirine is primarily of interest to researchers and collectors: well-formed crystals are treasured and occasionally cut into gemstones. Sapphirine has also been synthesized for experimental purposes via a hydrothermal process. Typical colours range from light to dark sapphire blue, bluish to brownish green, green, and bluish or greenish gray to black; less"
"jewelry. They also may be created synthetically in laboratories for industrial or decorative purposes in large crystal boules. Because of the remarkable hardness of sapphires – 9 on the Mohs scale (the third hardest mineral, after diamond at 10 and moissanite at 9.5) – sapphires are also used in some non-ornamental applications, such as infrared optical components, high-durability windows, wristwatch crystals and movement bearings, and very thin electronic wafers, which are used as the insulating substrates of very special-purpose solid-state electronics (especially integrated circuits and GaN-based LEDs). Sapphire is the birthstone for September and the gem of the 45th anniversary."
"Material properties of diamond Diamond is the allotrope of carbon in which the carbon atoms are arranged in the specific type of cubic lattice called diamond cubic. Diamond is an optically isotropic crystal that is transparent to opaque. Diamond is the hardest naturally occurring material known. Yet, due to important structural weaknesses, diamond's toughness is only fair to good. The precise tensile strength of diamond is unknown, however strength up to 60 GPa has been observed, and it could be as high as 90–225 GPa depending on the crystal orientation. The anisotropy of diamond hardness is carefully considered during diamond"
"also occur. In gemology, their luster is called adularescence and is typically described as creamy or silvery white with a ""billowy"" quality. It is the state gem of Florida. The gemstone commonly called ""rainbow moonstone"" is more properly a colorless form of labradorite and can be distinguished from ""true"" moonstone by its greater transparency and play of color, although their value and durability do not greatly differ. Orthoclase is one of the ten defining minerals of the Mohs scale of mineral hardness, on which it is listed as having a hardness of 6. NASA's Curiosity Rover discovery of high levels"
"to a very large kinetic energy barrier, diamonds are metastable; they will not decay into graphite under normal conditions. Material properties of diamond Diamond is the allotrope of carbon in which the carbon atoms are arranged in the specific type of cubic lattice called diamond cubic. Diamond is an optically isotropic crystal that is transparent to opaque. Diamond is the hardest naturally occurring material known. Yet, due to important structural weaknesses, diamond's toughness is only fair to good. The precise tensile strength of diamond is unknown, however strength up to 60 GPa has been observed, and it could be as"
"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"
"Chrysoberyl The mineral or gemstone chrysoberyl is an aluminate of beryllium with the formula BeAlO. The name chrysoberyl is derived from the Greek words χρυσός ""chrysos"" and βήρυλλος ""beryllos"", meaning ""a gold-white spar"". Despite the similarity of their names, chrysoberyl and beryl are two completely different gemstones, although they both contain beryllium. Chrysoberyl is the third-hardest frequently encountered natural gemstone and lies at 8.5 on the Mohs scale of mineral hardness, between corundum (9) and topaz (8). An interesting feature of its crystals are the cyclic twins called ""trillings"". These twinned crystals have a hexagonal appearance, but are the result"
"a supplement for the prevention and treatment of osteoporosis and arthritis. Carbon is the chemical element with atomic number 6, occurring as C, C and C. At standard temperature and pressure, carbon is a solid, occurring in many different allotropes, the most common of which are graphite, diamond, the fullerenes and amorphous carbon. Graphite is a soft, hexagonal crystalline, opaque black semimetal with very good conductive and thermodynamically stable properties. Diamond however is a highly transparent colourless cubic crystal with poor conductive properties, is the hardest known naturally occurring mineral and has the highest refractive index of all gemstones. In"
"color as the quantity of chromium increases. The deeper the pink color, the higher their monetary value. In the United States, a minimum color saturation must be met to be called a ruby, otherwise the stone is referred to as a ""pink sapphire"". ""Padparadscha"" is a delicate, light to medium toned, pink-orange to orange-pink hued corundum, originally found in Sri Lanka, but also found in deposits in Vietnam and parts of East Africa. Padparadscha sapphires are rare; the rarest of all is the totally natural variety, with no sign of artificial treatment. The name is derived from the Sanskrit ""padma"
"the Meenakshi Amman Temple in Madurai, is the goddess Meenakshi, whose idol is traditionally thought to be made of emerald. Emerald Emerald is a gemstone and a variety of the mineral beryl (BeAl(SiO)) colored green by trace amounts of chromium and sometimes vanadium. Beryl has a hardness of 7.5–8 on the Mohs scale. Most emeralds are highly included, so their toughness (resistance to breakage) is classified as generally poor. Emerald is a cyclosilicate. The word ""emerald"" is derived (via and ), from Vulgar Latin: ""esmaralda""/""esmaraldus"", a variant of Latin ""smaragdus"", which originated in (smaragdos; ""green gem""). Emeralds, like all colored"
"it in Sri Lanka. Chrysoberyl The mineral or gemstone chrysoberyl is an aluminate of beryllium with the formula BeAlO. The name chrysoberyl is derived from the Greek words χρυσός ""chrysos"" and βήρυλλος ""beryllos"", meaning ""a gold-white spar"". Despite the similarity of their names, chrysoberyl and beryl are two completely different gemstones, although they both contain beryllium. Chrysoberyl is the third-hardest frequently encountered natural gemstone and lies at 8.5 on the Mohs scale of mineral hardness, between corundum (9) and topaz (8). An interesting feature of its crystals are the cyclic twins called ""trillings"". These twinned crystals have a hexagonal appearance,"
"Mellite Mellite, also called honeystone, is an unusual mineral being also an organic chemical. Chemically identified as an aluminium salt of mellitic acid; that is, aluminium benzene hexacarboxylate hydrate, with the chemical formula AlC(COO)·16HO. It is a translucent honey-coloured crystal which can be polished and faceted to form striking gemstones. It crystallizes in the tetragonal system and occurs both in good crystals and as formless masses. It is soft with a Mohs hardness of 2 to 2.5 and has a low specific gravity of 1.6. It was discovered originally in 1789 at Artern in Thuringia, Germany. It has subsequently also"
"red, blue, green, yellow, brown, black, or (uncommon) violet. There is a unique natural white spinel, now lost, that surfaced briefly in what is now Sri Lanka. Some spinels are among the most famous gemstones; among them are the Black Prince's Ruby and the ""Timur ruby"" in the British Crown Jewels, and the ""Côte de Bretagne"", formerly from the French Crown jewels. The Samarian Spinel is the largest known spinel in the world, weighing . The transparent red spinels were called spinel-rubies or balas rubies. In the past, before the arrival of modern science, spinels and rubies were equally known"
"the 20th century; and a rare, 100 carat (20 g) orange-colored padparadschan sapphire from Sri Lanka, considered ""the mother of all pads."" The collection also includes the Midnight Star Ruby, a 116.75-carat deep purplish-red star ruby. Harry Frank Guggenheim Hall of Gems and Minerals The Guggenheim Hall is an exhibit at the American Museum of Natural History on the Upper West Side in Manhattan, New York City, that hosts one of the world's largest geology collections. It focuses on petrology, mineralization and the anthropology of gems and minerals. It is the permanent home of the Star of India, one of"
"and monumental sculpture, such as granite, are at least as hard as the gemstones, and others such as malachite are relatively soft but counted as hardstones because of their rarity and fine colour. Essentially, any stone that is often used in jewellery is likely to count as a hardstone. Hard organic minerals such as amber and jet are included, as well as the mineraloid obsidian. Hardstones normally have to be drilled rather than worked with edged tools to achieve a fine finish. Geologically speaking, most of the gemstones traditionally carved in the West are varieties of quartz, including: chalcedony, agate,"
"some of the company's products are ""simulants"" (such as their diamond simulants), their synthetic ruby and sapphire stones are not imitations – they have the same chemical and crystalline structure that is found in natural stones. The factory's FAQ says ""our rubies and sapphires are really ruby and sapphire!"" The Shelby Gem Factory also manufactures simulated citrine and topaz, along with other birthstone substitutes. As per the company website's FAQ section in 2017, below are the Mohs scale hardness values for some well-known gems along with Shelby gem products: The company's policy is to maintain the confidentiality of celebrity clients,"
"Emerald Lingam Emerald Lingams are established in many Hindu Temples in Tamil nadu. Emerald (Tamil: மரகதம்)is a variety of the mineral beryl (BeAl(SiO)) colored green by trace amounts of chromium and sometimes vanadium. The hardness of Beryl is 7.5–8 on the 10 point Mohs scale of mineral hardness. The toughness (resistance to breakage)of Emerald is classified as generally poor, hence most emeralds are highly included. Emerald is a green gemstone. Emerald means the shade of green color. Because of its green color, the term Emerald is employed. Emerald is also associated with the eighth planet Mercury in the Solar System."
"is not primarily defined by carat weight; this is different to most gemstones where the carat weight exponentially increases the value of the stone. The biggest factor in the value of amethyst is the color displayed. The highest grade amethyst (called ""Deep Russian"") is exceptionally rare and therefore, when one is found, its value is dependent on the demand of collectors. It is, however, still orders of magnitude lower than the highest grade sapphires or rubies (padparadscha sapphire or ""pigeon's blood"" ruby). Amethyst Amethyst is a violet variety of quartz. The name comes from the Koine Greek ἀμέθυστος ""amethystos"" from"
"Rhodium Rhodium is a chemical element with symbol Rh and atomic number 45. It is a rare, silvery-white, hard, corrosion-resistant and chemically inert transition metal. It is a noble metal and a member of the platinum group. It has only one naturally occurring isotope, Rh. Naturally occurring rhodium is usually found as the free metal, alloyed with similar metals, and rarely as a chemical compound in minerals such as bowieite and rhodplumsite. It is one of the rarest and most valuable precious metals. Rhodium is found in platinum or nickel ores together with the other members of the platinum group"
"ones, which are called rubies. The term ""Yogo sapphire"" refers only to sapphires from the Yogo Gulch. The cornflower blue color of the Yogo results from trace amounts of iron and titanium. Yogo sapphires are unique in that they are free of cavities and inclusions, have high uniform clarity, lack color zoning, and do not need heat treating because their cornflower blue coloring is uniform and deep. Unlike Asian sapphires, they maintain their brilliance in artificial light. Yogos present an advantage to gemcutters: since they are found as primary constituent minerals within an igneous bedrock rather than in sedimentary alluvial"
"production is also plagued by an as yet inescapable tint, which is usually a brownish green. A limited range of fancy colors have been produced as well, the two most common being blue and green. Natural minerals that (when cut) optically resemble white diamonds are rare, because the trace impurities usually present in natural minerals tend to impart color. The earliest simulants of diamond were colorless quartz (A form of silica, which also form obsidian, glass and sand), rock crystal (a type of quartz), topaz, and beryl (goshenite); they are all common minerals with above-average hardness (7–8), but all have"
"the softest known substances, and diamond, the hardest naturally occurring substance. It bonds readily with other small atoms, including other carbon atoms, and is capable of forming multiple stable covalent bonds with suitable multivalent atoms. Carbon is known to form almost ten million different compounds, a large majority of all chemical compounds. Carbon also has the highest sublimation point of all elements. At atmospheric pressure it has no melting point, as its triple point is at and , so it sublimes at about 3,900 K. Graphite is much more reactive than diamond at standard conditions, despite being more thermodynamically stable,"
"these translations as ""topaz"" all derive from the Septuagint translation ""topazi[os]"", which as mentioned above referred to a yellow stone that was not topaz, but probably ""chrysolite"" (chrysoberyl or peridot), it should be borne in mind that topaz is likely not meant here. An English superstition held that topaz cured lunacy. Topaz Topaz is a silicate mineral of aluminium and fluorine with the chemical formula AlSiO(F, OH). Topaz crystallizes in the orthorhombic system, and its crystals are mostly prismatic terminated by pyramidal and other faces. It is one of the hardest naturally occurring minerals (Mohs hardness of 8) and is"