$399 00. Save $350.00. CaS has been studied as a component in a process that would recycle gypsum, a product of flue-gas desulfurization.Like many salts containing sulfide ions, CaS typically has an odour of H 2 S, which results from small amount of this gas formed by hydrolysis of the salt. Fluorapatite is a hard crystalline solid. To counteract these anomalies and ensure crisp, clean images, the NIKKOR Z 70-200mm f/2.8 VR S employs two of Nikons most advanced lens coatings: Nano Crystal Coat for eliminating incidental light from a diagonal direction and ARNEO Coat for eliminating incidental Siderite is a mineral composed of iron(II) carbonate (FeCO 3).It takes its name from the Greek word sideros, "iron". The human eye responds to the wavelength region between 400 and 700 nanometers, which represents the The Nikon F-mount is a type of interchangeable lens mount developed by Nikon for its 35mm format single-lens reflex cameras.The F-mount was first introduced on the Nikon F camera in 1959, and features a three-lug bayonet mount with a 44 mm throat and a flange to focal plane distance of 46.5 mm. In the numerical aperture equation, n represents the refractive index of the medium between the objective front lens and the specimen, and or is the one-half angular aperture of the objective. Amorphous gems -- those with no crystal structure -- are also singly refractive. Refractive index: n = 1.631 - 1.650 n = 1.633 - 1.646: Birefringence: = 0.002: Ultraviolet fluorescence: Fluorescent and phosphorescent. Fluorite and HRI Elements; Show More. $1,996 95. A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction.A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (elements), usually arranged along a common axis.Lenses are made from materials such as glass or plastic, and are ground and polished or molded to a desired Painite is a very rare borate mineral.It was first found in Myanmar by British mineralogist and gem dealer Arthur C.D. Item Condition: 9 Minor scuffs & surface marks. 12 Mos. When subjects are backlit, incidental light can streak across the frame causing unwanted ghosting, reflections and flare. Gemstone Density Chart References: Fluorapatite, often with the alternate spelling of fluoroapatite, is a phosphate mineral with the formula Ca 5 (PO 4) 3 F (calcium fluorophosphate). Sodalite is a member of the sodalite group with hauyne, nosean, lazurite and tugtupite. It is a valuable iron mineral, since it is 48% iron and contains no sulfur or phosphorus. Diamond has many unequaled qualities and is very unique among minerals. Such minerals are transparent or translucent, and have a high refractive index (of 1.9 or more). They are classified into two main categories: the traditional refractive type and reflective.Each category is further divided Used Savings 25%. (iv) RI: the total range of refractive index shown by the mineral with this coulour is shown: fluorite IS colourless, blueish or purple 1.43 v. high - ISOTROPIC Late mineral in granites - often purple due to radiation damage. These two characteristics enable the lens to produce extremely sharp images. See also: Gemstone Hardness Chart. These new formulations allow for greatly improved correction of optical aberration. Stainless Steel refractive index & extinction coefficient at 632.8 nm are 2.75681 & 3.792016 Star Ruby 1.760 1.773 Staurolite 1.739 Steatite 1.539 Steel 2.50 Fluorite 1.434 Formica 1.47 Garnet, Almandine 1.760 Garnet, Almandite 1.790 Garnet, Andradite Diamond in general is the birthstone for April. Amazonite, also known as Amazonstone, is a green tectosilicate mineral, a variety of the potassium feldspar called microcline. Two High Refractive Index Elements; Super Spectra Coating; Show More. Some gemstones are singly refractive and have only 1 RI. As such, it is the only gemstone to have been initially identified from a faceted stone. Most pieces of the gem, prior to Taaffe, had been misidentified as spinel. Objectives. Calcium sulfide is the chemical compound with the formula Ca S.This white material crystallizes in cubes like rock salt. Pain who misidentified it as ruby, until it was discovered as a new gemstone in the 1950s.When it was confirmed as a new mineral species, the mineral was named after him. Sodalite (/ s o. For example, water ice is ordinarily found in the hexagonal form Ice I h, but can also exist as the cubic Ice I c, the rhombohedral ice II, and many other forms.The different polymorphs are usually called different phases. Larimar is the tradename for a rare blue variety of the silicate mineral pectolite found only in the Dominican Republic, around the city of Barahona. HRI High Refractive Index Lens 2.01 6 Mos. Feldspars make up about 60% of the Earth's crust, and 41% of the Earth's continental crust by Note: Many authors use the variable to designate the one-half angular aperture while others employ the more common term , and in some instances, .. Adamantine minerals possess a superlative lustre, which is most notably seen in diamond. It is typically blue, but natural "fancy" sapphires also occur in yellow, fluorite: 1.387: franklinite: 2.36: material index; glass, borosilicate (pyrex) 1.475: glass, crown (soda-lime) which is defined as the difference between the refractive indices for for two prominent lines in the spectrum of hydrogen the blue F line at 486.1 nm and the red C line at 656.3 nm. Li 2 O : Molar mass: 29.88 g/mol Appearance white solid Density: 2.013 g/cm 3: Melting point: Corrosive, reacts violently with water NFPA 704 (fire diamond) Singly refractive gems include diamond, spinel and all the garnets, as well as other cubic crystals like cuprite, fluorite and sphalerite. Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide (-Al 2 O 3) with trace amounts of elements such as iron, titanium, chromium, vanadium, or magnesium.The name sapphire is derived from the Latin "saphirus" and the Greek "sapheiros", both of which mean blue. Refractive index: 1.4331.448: Fusibility: 3: Solubility: slightly water soluble and in hot hydrochloric acid: Other characteristics: May be fluorescent, phosphorescent, thermoluminescent, and/or triboluminescent: References: Fluorite (also called fluorspar) is the mineral form of Its chemical formula is KAlSi 3 O 8, which is polymorphic to orthoclase.. Its name is taken from that of the Amazon River, from which green stones were formerly obtained, though it is unknown whether those stones were amazonite. Its low refractive index reduces the need for anti-reflection coatings. Peridot (/pr.dt, -do/ PERR-ih-dot, -doh), sometimes called chrysolite, is a deep yellowish-green transparent variety of olivine.Peridot is one of the few gemstones that only occurs in one color. The following table lists these values for a variety of stones found in jewelry and gem collections. Polymorphism is the ability of a solid to exist in more than one crystal form. $298 95. To attain higher working numerical apertures, many objectives are designed to image the specimen through another medium that reduces refractive index differences between glass and the imaging medium. 12 Mos. For gemologists, refractive index and double refraction (birefringence) serve as important clues for identifying gems. Objectives allow microscopes to provide magnified, real images and are, perhaps, the most complex component in a microscope system because of their multi-element design. a transmissive optical device) that is typically worn in front of the eye to improve daily vision.The most common use is to treat refractive errors: myopia, hypermetropia, astigmatism, and presbyopia. Taaffeite (/ t f a t /; BeMgAl 4 O 8) is a mineral, named after its discoverer Richard Taaffe (18981967) who found the first sample, a cut and polished gem, in October 1945 in a jeweler's shop in Dublin, Ireland. It is the hardest known substance, it is the greatest conductor of heat, it has the highest melting point of any substance (7362 F or 4090 C), and it has the highest refractive index of any natural mineral. The same group of atoms can often solidify in many different ways. $1,696 95. Item Condition: 9+ Little to no signs of wear. Optical finery includes two aspherical elements, one dual spherical element, one ED (Extra-low Dispersion) element, three Super ED elements, and two HR (High Refractive index) elements. In examining the equation, it becomes apparent that resolution is directly proportional to the illumination wavelength. Due to its rarity, painite can cost in the range of between US$50,000 to $60,000 per carat. Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases, is an opaque, impure variety of silica, usually red, yellow, brown or green in color; and rarely blue.The common red color is due to iron(III) inclusions.Jasper breaks with a smooth surface and is used for ornamentation or as a gemstone.It can be highly polished and is used for At 30% Off, use this code: 30% OFF Get a 40% Discount - For orders 12 items or more, use this code: 40% OFF ONE MORE WEEK, TILL NOVEMBER 8TH Fluorite has a very low refractive index and a very low dispersion. High Objectives are available with magnifications ranging from 2X 200X. d l a t / SOH-d-lyte) is a tectosilicate mineral with the formula Na 8 (Al 6 Si 6 O 24)Cl 2, with royal blue varieties widely used as an ornamental gemstone.Although massive sodalite samples are opaque, crystals are usually transparent to translucent. Thin-film interference is a natural phenomenon in which light waves reflected by the upper and lower boundaries of a thin film interfere with one another, either enhancing or reducing the reflected light.When the thickness of the film is an odd multiple of one quarter-wavelength of the light on it, the reflected waves from both surfaces interfere to cancel each other. A corrective lens is a lens (i.e. [citation needed] Doped calcium fluoride, like natural fluorite, exhibits thermoluminescence and is used in thermoluminescent dosimeters. The index of refraction. Diamond is number 10 on the Mohs scale, and is approximately 4 times harder than Corundum, which is It is the only common mineral with four directions of perfectly shaped cleavage. Promo Financing with Fluorite and HRI Elements; Show More. Used Savings 15%. Feldspars are a group of rock-forming aluminium tectosilicate minerals, containing also other cations such as sodium, calcium, potassium, or barium. After 23 years, were closing our website in December. Contact lenses are worn directly on the surface of the eye. Fluorite: 1.434: none: Sellaite: 1.378-1.390: 0.012: Opal: 1.370-1.520: none: Villiaumite: 1.327: anomalous: Notes. Two High Refractive Index Elements; Super Spectra Coating; Show More. [citation needed] It also allows much smaller wavelengths to pass through. Reg. Now that they're using FL elements, they've updated their glossary entries to sing the praises of fluorite instead of only highlighting the weaknesses. We're having a sales on all our $1- $599 Gemstones!! Like the rest of their kind, these violet and purple rocks are the hardest of minerals, and display extraordinary brilliance owing to their high refractive index, making them the most expensive of purple gemstones, with prices of up to $1.5M a carat. Glasses or "spectacles" are worn on the face a short distance in front of the eye. Also a cement in sandstones. Its insolubility in water is convenient as well. Fluorite is easily identifiable by hardness, cleavage, and specific gravity. Everythings wrapped up in a dust, splash and freezeproof casing that features a lens function button and manual focus clutch. Adamantine lustre. However, fluorite easily cracks and is sensitive to temperature changes that can adversely affect focusing by altering the lens' refractive index." The most common members of the feldspar group are the plagioclase (sodium-calcium) feldspars and the alkali (potassium-sodium) feldspars. where R is the separation distance, is the illumination wavelength, n is the imaging medium refractive index, and is one-half of the objective angular aperture. Fluorite objectives are produced from advanced glass formulations that contain materials such as fluorspar or newer synthetic substitutes. 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