Stone Info_ Tourmaline-Peridot-Zircon PDF

*****Tourmaline, Peridot, Zircon ***** LARGEST CONSUMERS : Tourmaline: Chinese have historical love for the stone, Paraíba Tourmaline: high demand in Japan Pink tourmaline: exported to China to satisfy the demand carved pink tourmaline Zircon: popular due to the home shopping network, blue zircons b...

*****Tourmaline, Peridot, Zircon ***** LARGEST CONSUMERS : Tourmaline: Chinese have historical love for the stone, Paraíba Tourmaline: high demand in Japan Pink tourmaline: exported to China to satisfy the demand carved pink tourmaline Zircon: popular due to the home shopping network, blue zircons being the most populare MOHS SCALE: Peridot: 6.5 to 7, scratches more easily as well as prone to abrasions and senstive common cleaning methods, so warm water and soap are best Zircon: 7 to 7.5, but is brittle and prone to abbrasion VARIETY/SPECIES/GROUP: Tourmaline: species are elbaite, liddicoatite, dravite, uvite, and schorl, most gem tourmalines are ebaites rich in sodium, lithium, aluminum, and sometimes—but very rarely—copper where elements like lithium and sodium are concentrated -Liddicoatite is rich in calcium, lithium, and aluminum -Uvite is rich in calcium, magnesium, and aluminum forming into metamorphosed limestone -Dravite is rich in sodium, magnesium, and aluminum. It also forms in metamorphosed limestone -Schorl is typically black and rich in iron. It forms in a wide variety of rock types, rare made into gems but used in mourning jewelry COLOR/HUE RANGE/VALUE: Tourmaline: green, blue, or yellow, pink to red, colorless, or zoned in a combination of colors -Watermelon tourmaline: zoned parallel to crystal length, red crystal with a green overgrowth -“Savannah” tourmalines are also mixtures of uvite and dravite, bright yellow color due to iron -Chrome Tourmaline: trade term for a vibrant green tourmaline colored by traces of vanadium, chromium, or both with vibrate color in small & medium sizes, strong bluish green to very slightly yellowish green Paraíba Tourmaline: range of greenish blue, bluish green, green, blue, and violet hues, highest valued tourmaline type Green & Blue Tourmaline: range of hues from blue and very strongly greenish blue to yellowish green, Blue tourmalines are typically darker in tone, less transparent, and less brilliant than green tourmalines which have pastel hues Red & Pink Tourmaline(rubellite): purplish red to orange-red, sometimes the term 'Rubellite" is only used for most saturated purplish red or red tourmaline, Pink tourmaline ranges from light pastel shades to a vibrant pink, vivid and strongly saturated pinks are the most in demand Cat's Eye Tourmaline: various shades of pink, red, green, blue, and greenish blue Peridot: yellowish green to greenish yellow,finest hue is green without any hint of yellow or brown, colors is at its finest in stones weighing 10 cts. and above Zircon: Colorless,yellow, green, red, reddish brown, and blue hues a result of heat treatment-includes very slightly greenish blue, greenish blue, very strongly greenish blue, naturally zircons yellowish or reddish brown CHEMICAL COMPOSTION: Tourmaline: silicates that share the elements aluminum, boron, and fluorine, traces elements of iron, and possibly titanium, induce green and blue colors, Manganese- reds, pinks, and possibly yellows, yellow and pink to red elbaites hues caused by radiation Paraiba Tourmaline: large amounts of trace elements like manganese and copper, copper causes its color Blue & Green Tourmaline: trace elements of iron Red and Pink Tourmaline (Rubellite): trace elements of manganese, although some pink tourmaline have trace element of titanium or by color centers induced by natural or manmade radiation Peridot: silicate of iron and magnesium, trace elements of iron create it s hue FORMING SOURCE: Tourmaline: pegmatites Paraíba Tourmaline: formed in pegamaites, Peridot: volcanic rocks called basalts,very rarely, as large crystals lining veins or pockets in certain types of igneous rocks Zircon: igneous and metamorphic rocks CRYSTAL STRUCTURE: Tourmaline: elongated with a rounded triangular cross-section Paraiba Tourmaline: copper inclusions COMMON CUTS: Tourmaline: long rectangles due to crystal structure, fashioned gem based on its depth of color, to darken light rough orient a gem’s table so that it’s perpendicular to the crystal’s length, To lighten dark rough, they orient a finished gem’s table so that it’s parallel to the crystal’s length Paraíba Tourmaline: due to its high value they are almost always custom cut, faceted into brilliant cuts, commonly pear and oval shapes and usually 1ct or large depending on color Green & Blue Tourmaline: dark stones are cut with the table parallel to the length of the crystal which can make them strongly dichroic (showing brownish or yellowish color component) described as “oily” or “olive” green - Chrome tourmalines: often flattened to due to the crystal structure resulting in shallow proportion but can be commonly cut up to 5ct, popular calibrated sizes are 6×4-mm & 7×5-mm ovals and 5×5-mm hearts and 6×4mm pears., high demand for good-quality, free-size stones above 8×6 mm Red & Pink Tourmaline: Pink gems can be up to 50-ct. sizes but most are limited above 20 cts. Red tourmalines are available in sizes up to 20 cts, calibrated sizes are 6×4-mm, 7×5-mm, and 8×6-mm ovals and octagons, and rounds of 2.5 to 5 mm Cat's Eye Tourmaline: cabochons, cutters orient bicolor material so the eye appears to float between two colors Zircon: hard to cut due to being brittle, usually brillant cut to show off its luster and fire, “zircon cut” was also created which uses eight extra facets on the pavilion, also found in step cuts and mixed cuts COUNTRIES OF ORIGIN: Tourmaline: Brazilian state of Minas Gerais is largest produces of many colors of tourmaline, Brazilian state of Minas Gerais, also found in Africa -Nigeria, Zambia, Mozambique, Madagascar, Namibia, Tanzania, and Kenya, Afghanistan and Pakistan, Russian and US in San Diego County, Ca - Bamburrio JackPot: in the Minas Gerais, Brazil’s mining area the Jonas Mine was the greatest single deposit of Rubellite, yield millions of gem quality stones, the largest being "Joninha" 775lbs sold to a private US collector for over 1 million Paraiba Tourmaline: northern Brazilan states of Paraíba and Rio Grande do Norte- discovered by Barbosa, African source were discovered and given trade names “African Paraíba” and “Paraíba-like” , they are less quality then Brazil ans typically heat treated Green & Blue Tourmaline: Brazil(the best tourmaline), Afghanistan, the United States, and Africa, Fine chrome tourmaline comes from Myanmar, most material comes from Tanzania and Kenya in Africa Red & Pink Tourmaline: Brazil’s Cruzeiro mine in Minas Gerais is the major source for red, Nigeria’s Oyo State produces red rubellite, 1899 to 1914 Southern California- San Diego County’s Himalaya mine producesd pink tourmaline, fine red tourmaline include Madagascar and Afghanistan Peridot: United States, China, and Vietnam, in igneous rock Zabargad, Finland, Pakistan, and Myanmar, finest large peridots come from Myanmar and Himalayas of Pakistan( which come out with superior gems as high as 50ct), Commercial material -China & United States- Apache American Indian tribe mine much of the world’s commercial peridot on the San Carlos Reservation in Arizona,Vietnam, Mexico, Australia, Ethiopia, Norway, Sri Lanka, and the US state of New Mexico Zircon: Southeast Asia,Madagascar, Sri Lanka, Myanmar, Vietnam, Cambodia, and Australia POSSIBLE PHENOMENA: Tourmaline: color zoning, doubly refractive and pleochroic, most green tourmalines are strongly pleochroic Cat Eye Tourmaline: parallel inclusions, fairly large, hollow tubes rather than fine needles Peridot: strongly doubly refractive Zircon: refractive index, double refraction, and specific gravity CLARIETY CHARACTERISTIC: Tourmaline: trichites, long hollow tubes with crystals, gas bubble or water are common, Red & Pink Tourmaline: inclusions are common and some eye visible ones are accepted, but they can affect overall price Peridot: eye-clean, with inclusions—minute octahedral crystals of the mineral chromite, calibrated gems are grade as either “grade A”—is eye-clean with a pure, yellowish green hue and no brownish component, “grade B" clean but pale in color, or included but of reasonably good color—maybe just a touch of brown. Zircon: relatively free of inclusions outside cloudy or smoky appearance, radioactive elements—either uranium or thorium can break down the crystal structure making them 'Metamict", when this is the case the they are referred to as "Low Zircon", Metamict zircons are usually green, they are grades as high- intermediatelow based on physical and optical properties, high zircon are used for jewelry, COMMON TREATMENTS: Tourmaline: heating and irradiation usually lighten and brighten the original color, irradiation is can sometimes fade but it can turn solid green material into a colorful mix of green and red, light yellows and greens to darker yellows and oranges Red & Pink Tourmaline: strong pink gems on the market result from irradiation of near-colorless, pale pink, yellow, or brown material, irradiated tourmaline might fade with exposure to light or heat, fracture filling resins or polymers. Paraiba Tourmaline: grayish blue ones, are heat treated, fracture filling resins or polymers. Cat's Eye Tourmaline: treated with acid to remove unsightly inclusions or dark staining in the hollow tubes,tubes sealed off with epoxy resin Zircon: heat can repair the Metamict, multiple heat treatments can be done to adjust color TRADES NAMES: Paraiba Tourmaline: “electric,” “turquoise,” “sapphire” or “tanzanite” blue, and “mint” green Blue Tourmaline: " indicolite" - Green Tourmaline: "verdelite" Red and Pink Tourmaline: " Rubellite", Pink tourmaline can be called “hot pink” or “bubblegum pink. Peridot: “lily pads” dark chromite crystals or reflective inclusions whose unusual shape earned them the name Zircon: heat treated to make colorless is called "Matura Diamonds " MAIN SYNTHETIC PROCESS: COMMON IMITATION MATERIAL: CUTTING/TRADING CENTER: Blue and Green Tourmaline: China, Thailand, and Jaipur, India Red & Pink Tourmaline: primarily to cutters in Germany’s Idar-Oberstein and Bangkok, Thailand, later China became the primary cutting operations Peridot: Burmese peridot is cut in Thailand, Germany’s Idar-Oberstein formerly bought most Arizona peridot to cut themselves but ended up out sourcing to Thailand Zircon: Thailand