if (printReadyElem != null) { © John Veevaert, Comments: Carlsbad twinned crystal of orthoclase. Orthoclase, or orthoclase feldspar (endmember formula K Al Si 3 O 8), is an important tectosilicate mineral which forms igneous rock.The name is from the Ancient Greek for "straight fracture," because its two cleavage planes are at right angles to each other. According to the scale, Talc is the softest: it can be scratched by all other materials. All of the feldspar minerals exhibit a blocky crystal habit, hardness greater than glass, and two directions of cleavage that meet at nearly right angles. It has a vitreous luster. Hardness : 6. When set in gold, the yellow tones of orthoclase are showcased. Orthoclase is a member of the Potassium Feldspars of the Feldspar Group of minerals that also includes Albite, Amazonite, Andesine, Anorthite, Bytownite, Hyalophane, Labradorite, Moonstone, Oligoclase, Orthoclase, Sanidine and Sunstone. Glass is assigned a Mohs hardness number of 5.5 because it will scratch apatite (Mohs' hardness number = 5) but will not scratch orthoclase feldspar (Mohs' hardness number = 6). It can form on most granites and pegmatites, as well as being one of the main chemical components of Moonstone. Orthoclase is said to have a soothing effect on its wearer. Learn about technical details and facts surrounding the... Find the gemstones for a specific date and time, Toll Free Orthoclase is difficult to identify from other gemstones by appearance alone. var gAutoPrint = true; // Flag for whether or not to automatically call the print function This chakra is associated with the color yellow, self-confidence, positive will, productivity, genuine laughter and warmth. Orthoclase is frequently known as potassium feldspar or K-spar, and is easily distinguished from the plagioclase feldspars in hand sample by its lack of striations. The gem known as moonstone is largely composed of orthoclase. Mindat.org's Discussion Groups { Keyboard Orthoclase, or orthoclase feldspar (endmember formula K Al Si 3 O 8), is an important tectosilicate mineral which forms igneous rock.The name is from the Greek for "straight fracture," because its two cleavage planes are at right angles to each other. Transparent materials are faceted and opaque materials are usually cut en cabochon. Feldspar (mineral group name), from Swedish names for field (feldt or falt) and spar (spat), in reference to the spar in tilled fields overlying granite; in German the word became Feldspat. length x width x depth, { var headTags = document.getElementsByTagName("head"); Prismatic - Crystals Shaped like Slender Prisms (e.g. The accompanying table sho… feldspars). Formation and Subtypes. The test should be made in an inconspicuous place such as the girdle of a cut stone. Crystals can be easily damaged or split. Feldspars are an important component of many building stones, but in economic terms these minerals are more important for what they become than what they are. Orthoclase (Feldspar KAlSi 3 O 8) Categories: Ceramic; Oxide; Aluminum Oxide; Silicon Oxide. Compositions of foremost elements in commonplace feldspars may be expressed in terms of 3 endmembers: potassium feldspar (K-spar) endmember KAlSi3O8, albite endmember NaAlSi3O8, anorthite endmember CaAl2Si2O8. Orthoclase feldspar may arise from regional metamorphic processes, and is a common ingredient in various crystalline schists (Table 6.1). Since orthoclase has a hardness of 6 to 6.5, simply wiping the dust off an orthoclase gemstone can gradually reduce its polish. Luster: Vitreous (Glassy) Streak: white : Optical Properties of Orthoclase : Gladstone-Dale: CI meas= 0.011 (Superior) - where the CI = (1-KPDmeas/KC) CI calc= 0.007 (Superior) - where the CI = (1-KPDcalc/KC) KPDcalc= 0.2044,KPDmeas= 0.2036,KC= 0.2058 Ncalc = 1.52 - 1.53 : Optical Data: In the Mohs system, hardness is represented by a number MH increasing from 1 to 10 according to scratch resistance and orthoclase is defined by number MH = 6, lying between apatite, MH = 5, and quartz, MH = 7. The name was changed in 1823 to orthoklas by Johann Friedrich August Breithaupt. In glassmaking, alumina from feldspar improves product hardness, durability, and resistance to chemical corrosion. A large component of ordinary dust is quartz, with a hardness of 7 on the Mohs scale. Luster/Transparency : pearly, vitreous/translucent. Moonstone is a name given to a gem material that consists of very thin, alternating layers of orthoclase (an alkali feldspar) and albite (a plagioclase feldspar). function printSpecial() Useful charts and list as reference and lookup recourse, The easy way to find the gemstones sorted by color. Why? It is best to wrap gemstones in soft cloth or place them inside a fabric-lined jewelry box. html += '\n\n'; This lies between the hardness of a steel knife (5.5) and the hardness of quartz (7). A feldspar mineral is an abundant rock-forming mineral typically occurring as colourless or pale-coloured crystals. may not work well with some computers. Comments: Striated, dark violet crystal of lorenzenite in cream-colored orthoclase. Weathering end products: Kaolinite illite. (Healing Crystal, Ascension Crystal) Hardness: 5.5 - 6.0 Origin: Madagascar. In thin section, alkali feldspar grains often look like they’re sprinkled with dirt (PPL) or tiny confetti (XPL). Dispersion relatively strong. The specific gravity depends strongly on composition and varies between 2.5-2.9 g/cm 3. Over half the Earths crust is composed of a single group of minerals known as the feldspars. Español In cavities in basalts; in high-grade metamorphic rocks and as a result of potassic hydrothermal alteration; also authigenic and detrital. It is a type of potassium feldspar, also known as K-feldspar. Streak=White or Colorless. Therefore, orthoclase is sometimes also called "K-spar". Gem quality materials are typically champagne, golden yellow or greenish. Alternate names are potassium feldspar and K-feldspar. Detailed description, properties, locality information guide about the potassium feldspar mineral orthoclase and adularia. The largest selection of gemstone articles online... See an extensive selection of articles about birthstones, Fascinating details of ancient gemstones facts and stories, Learn about the healing effects of different gemstones. drag2 - RMB Resize/Rotate Solid answers between K-feldspar and albite are referred to as “alkali feldspar”. An important rock forming mineral occurring in basic igneous (granite, syeite, granodiorite) and metamorphic. In thin section, alkali feldspar grains often look like they’re sprinkled with dirt (PPL) or tiny confetti (XPL). Orthoclase gemstones are typically champagne yellow, golden yellow or greenish, though they can be other colors. Get Price It is a type of potassium feldspar, also known as K-feldspar.The gem known as moonstone (see below) is largely composed of orthoclase. They all have a vitreous luster that is often pearly on cleavage faces. Feldspars can be divided into three composition types: plagioclase feldspars, alkali feldspars, and barium feldspars. Rockhounds Discussion Group on Yahoo Groups Orthoclase is faceted into attractive gemstones and also has an industrial use as a scouring agent in the making of some glasses and ceramics. In fact, feldspar is the standard for hardness 6 in the Mohs scale. Hardness is 6 ; Specific Gravity is approximately 2.53 - 2.56 (average) Streak is white. Orthoclase gemstones have not attained world-fame, but a rare 250 carat yellow faceted orthoclase gemstone from Madagascar is displayed at the Smithsonian National Museum of Natural History in Washington D.C., USA. Orthoclase is frequently known as potassium feldspar or K-spar, and is easily distinguished from the plagioclase feldspars in hand sample by its lack of striations. Orthoclase Meanings, Zodiacs, Planets, Elements, Colors, Chakras, and more. A - Atoms On/Off Warning: this large pop-up is very compute intensive and Although there are many feldspar minerals, they all share a tight range of physical properties that are surprisingly consistent. The sense of Haüy's name was that the mineral was a feldspar, but he did not specify a type-locality, nor did Haüy give a chemical analysis. } Together with the other potassium feldspars, orthoclase is a common raw material for the manufacture of some glasses and some ceramics such as porcelain, and as a constituent of scouring powder. (Healing Crystal, Ascension Crystal) Hardness: 5.5 - 6.0 Origin: Madagascar Location: Zarzalejo, Madrid. Orthoclase – from Greek for straight and fracture, in reference to the cleavage angle, which is 90°. html += headTags[0].innerHTML; Rocks are made up of one or more minerals. { Massive - Granular - Common texture observed in granite and other igneous rock. Solid solutions among albite and anorthite are called “plagioclase”,or greater nicely “plagioclase feldspar”. Orthoclase gemstones are typically champagne yellow, golden yellow or greenish, though they can be other colors. } Orthoclase is an important mineral in the feldspar group, and the chemical formula of the mineral is KAlSi 3 O 8. The chemical formula for orthoclase is KAlSi 3 O 8 and the composition of this mineral is: potassium (K) -14.05%, aluminum (Al) – 9.69%, silicon (Si) – 30.27%, and oxygen (O) – 45.99%. Help on Above. { Orthoclase is found in Madagascar, Burma (Myanmar) and Kenya. Keyboard According to traditional Hindu beliefs, orthoclase benefits the "Manipura" or solar plexus chakra. The name is from the Ancient Greek for “straight fracture,” because its two cleavage planes are at right angles to each other. Orthoclase has several commercial uses. 406 – Orthoclase Feldspar (Mineral), Luster: Non-Metallic Vitreous, Hardness: 6, Breakage: 2 cleavage planes intersecting at 90 degrees, Description: Silicate mineral, blocky-looking, usually a pink/light orange color, most common mineral on Earth’s surface (feldspar literally means “field rock”) Physically, orthoclase is believed to protect internal organs, strengthen bones and boost energy. Blocky - Crystal shape tends to be equant (e.g. Orthoclase feldspar is a tectosilicate mineral which is most commonly found in igneous rock. Hardness - Greater than 5.5. Orthoclase feldspar may arise from regional metamorphic processes, and is a common ingredient in various crystalline schists (Table 6.1). Do not use harsh chemical or cleaners and avoid ultrasonic cleaners and steamers. The name, "orthoclase" is a Greek word meaning "straight fracture", which refers to the cleavage planes of orthoclase being at right angles to each other. All feldspars have a hardness of about six on the Mohs scale, which falls between a steel knife (5.5) and quartz (7). alert("Could not find the printReady section in the HTML"); S - Stereo Pair on/off Application of KFeldspar in the Making of Jewelry. } Orthoclase is often colorless or champagne-colored, but it can also be pink, green, orange or bluish. The common feldspar of granites, granite pegmatites, and syenites. Manufacturer of Feldspar Mineral - Orthoclase Feldspar Mineral, Potash Feldspar Mineral, Potassium Feldspar Mineral offered by Sree Sai Krishna Minerals, Kadapa, Andhra Pradesh. It is a type of potassium feldspar, also known as K-feldspar.The gem known as moonstone (see below) is largely composed of orthoclase. Orthoclase belongs to the feldspar family of minerals, which also includes moonstone, amazonite, spectrolite and labradorite, Orthoclase is a transparent yellow feldspar resembling citrine quartz or yellow beryl, found primarily in Madagascar. tourmaline). if (gAutoPrint) Hand Specimen identification: Hardness, luster, cleavage, habit, and association help identify microcline, but it is easily confused with other feldspars, especially orthoclase, its poly-morph (see orthoclase).Distinctive microcline twinning or a bluish green color are diagnostic but may not be present or visible see Figure 5. The minerals of the plagioclase series are listed in the table below along with their relative abundance of albite (Ab) and anorthite (An). Orthoclase changes to kaolinite (Section 5.2.1.2) and sericite with the process of kaolinization and sericitization, respectively. Therefore, extra care should be taken when setting, repolishing or recutting orthoclase. Hand Specimen identification: The luster, hardness, and color of orthoclase are similar to other feldspars, but (in contrast with pla-gioclase) orthoclase is frequently pink or flesh col-ored, has cleavage planes that meet at 90o, and does not show twin striations.Association with other fel-sic minerals also helps identification. Streak : white. P - Polyhedra On/Off Extreme hardness and angular shape is suitable for railway ballast, roads, walls, roofing/flooring, stair steps, high-purity ferrosilicon, industrial silica sand and silicon carbide. var html = '\n\n'; Note: Buy colored gemstones by size and not by carat weight. printWin.document.close(); Golden Orthoclase Crystal #12 measures approximately 1 1/8" x 11/16" x 9/16" (28mm x 17mm x 13mm) and weighs .4 ounces (10.9 grams). Feldspar is a common raw material used in glassmaking, ceramics, and to some extent as a filler and extender in paint, plastics, and rubber. They usually have a glassy luster. Cleavable, granular, massive. The choice of a feldspar as standard Point Group: 2=m: Crystals commonly short prismatic along [100] or [001], tabular on [010], to 20 cm. They have glasslike luster making them a valuable resource in the jewelry industry. Hand Specimen identification: Hardness, luster, cleavage, habit, and association help identify microcline, but it is easily confused with other feldspars, especially orthoclase, its poly-morph (see orthoclase).Distinctive microcline twinning or a bluish green color are diagnostic but may not be present or visible see Figure 5. Point Group: 2=m: Crystals commonly short prismatic along [100] or [001], tabular on [010], to 20 cm. Plagioclase is the name of a group of feldspar minerals that form a solid solution series ranging from pure albite, Na(AlSi3O8), to pure anorthite, Ca(Al2Si2O8). Click HERE This group of minerals includes tectosilicates. The solution is to clean your orthoclase gemstones using a soft cloth and only mild soap or detergent if needed. Materials that display opalescence are classed as moonstone. Gem varieties vary in density, so carat weight is not a good indication of size, Precious and Semi-Precious Gemstone Glossary, Colorless, yellow, orange, pink, green, bluish. printWin.print(); { Therefore, orthoclase is sometimes also called "K-spar". Science & Origin of OrthoclaseOrthoclase, also known as K-spar and K-feldspar, is a common potassium feldspar mineral that crystallizes in the form of masses, small prismatic shards, elongated crystals, and thin plate-like layers. © Fabre Minerals, Mouse Material Notes: Two cleavage directions. if (document.getElementsByTagName != null) As feldspars weather they produce clay minerals and aluminum ores, two resources used throughout our modern society. Orthoclase is a rare gemstone that belongs to the feldspar group, which also includes moonstone, amazonite, spectrolite and labradorite. Together with their non-metallic luster and typically opaque character, these properties will usually distinguish feldspars from other common non-metallic minerals. Location: Rhonegletscher, Switzerland. Another property … } 1-800-464-1640 var printWin = window.open("","printSpecial", 'toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes,copyhistory=yes,width=350,height=350'); Drag2 - Resize Feldspars usually are white or nearly white, though they may be clear or light shades of orange or buff. "); Microcline is polymorphous with Orthoclase and Sanidine.These three minerals form the Potassium Feldspar group.They are almost identical in physical properties, and sometimes it is impossible to distinguish one another without x-ray analysis. The major mineral components of potassium feldspar are amazonite, moonstone, and orthoclase. _uacct = "UA-3067463-1"; if (headTags.length > 0) Location: Khibiny Massif, Kola Peninsula, Russia. M - Menu Golden Orthoclase Crystal #12 measures approximately 1 1/8" x 11/16" x 9/16" (28mm x 17mm x 13mm) and weighs .4 ounces (10.9 grams). else Drag1 - Manipulate Crystal The name is from the Ancient Greek for “straight fracture,” because its two cleavage planes are at right angles to each other. Hardness is the resistance of a substance to being scratched by another material. Orthoclase: pink granite mohs hardness and moonstone the mineral orthoclase information pictures wikipedia Colored stones vary in size-to-weight ratio. Link to . drag1 - LMB Manipulate Structure Hardness - Greater than 5.5. The material is either transparent or translucent. Streak=White or Colorless. Cleavage/Fracture : 90° cleavage angle; perfect (001), good (010), poor {110}/uneven. if (document.getElementById != null) Specific Gravity2.56. Feldspar is a common raw material used in making, ceramics, and to some extent as a filler and extender in paint, , and rubber. Orthoclase KAlSi3O8 °c 2001 Mineral Data Publishing, version 1.2 Crystal Data: Monoclinic. In order to keep orthoclase gemstones in good condition, some care is necessary. These different directions encounter different bonding environments in the kyanite crystal. Feldspar - Feldspar - Crystal structure: Sanidine and orthoclase are monoclinic or nearly so; the plagioclase feldspars are triclinic. Feldspar is the most common mineral in the Earth’s crust, so you are very likely to find it in the rocks you collect! Identifying Feldspars. © 2005-2020 GemSelect.com all rights reserved. Orthoclase is a member of the Potassium Feldspars of the Feldspar Group of minerals that also includes Albite, Amazonite, Andesine, Anorthite, Bytownite, Hyalophane, Labradorite, Moonstone, Oligoclase, Orthoclase, Sanidine and Sunstone. a = 8.625, b = 12.996, c = 7.193, Z = 4; beta = 116.016° V = 724.57 Den(Calc)= 2.55. An example of this type of cleavage can be seen in the accompanying photo. Orthoclase was named for those in 1801 by Rene Just Haüy from the Greek word orthos meaning right in allusion to the cleavage angle. Always remove orthoclase jewelry before engaging in vigorous physical activity. … Orthoclase is usually seen in yellow colors, being transparent to translucent. Meet some other silicate minerals! html += '\n\n\n'; Ask-A-Mineralogist from the Mineralogical Society of America } Orthoclase KAlSi 3 O 8: White or colorless Streak: 2 Directions, nearly 90° Pink, white or blue-green. Most of them exhibit two directions of perfect cleavage that intersect at or close to ninety degrees. Orthoclase is opaque to transparent and good quality specimens are eye clean. The names of the minerals in the series are arbitrarily given based upon their relative abundance of albite and anorthite. In ceramics, the alkalis in feldspar (calcium oxide, pota. From the Greek orthos - "right" and kalo -" I cleave" in allusion to the mineral's right angle of good cleavage. International: I - Indicies The solution is to clean your orthoclase gemstones using a soft cloth and only mild soap or detergent if needed. What is the Difference Between Orthoclase and Plagioclase? }. Clear gemstones such as white sapphire compliment orthoclase well. Orthoclase possesses perfect cleavage, which means gemstones can be split with a single blow, much like topaz. Although petrologists had used twinning as a method of distinguishing orthoclase from microcline, Wright and Stewart (1958) used the difference in certain d values to calculate a degree of disorder of a sample and thus have a quantitative method to identify the structural state of a potassium feldspar. B - Bonds On/Off H=6.0: Your Mineral is Orthoclase feldspar! Colorless, Greenish, Grayish yellow, White, Pink. Orthoclase, also known as K-spar and K-feldspar, is a common potassium feldspar mineral that crystallizes in the form of masses, small prismatic shards, elongated crystals, and thin plate-like layers. 2 Directions of Cleavage - Nearly right angles. All of the feldspar minerals exhibit a blocky crystal habit, hardness greater than glass, and two directions of cleavage that meet at nearly right angles. Some stones are larger and others are smaller than diamonds by weight in comparison. Please refer to our Gemstone Glossary for details of gemology-related terms. Do not use harsh chemical or cleaners and avoid ultrasonic cleaners and steamers. Feldspars show perfect or very good cleavage in two dimensions. Associated Minerals are quartz, plagioclase feldspars, micas, garnets, tourmalines and topaz. Would you like to learn more about the potassium feldspars? Orthoclase feldspar (endmember formula KAlSi3O8), is an important tectosilicate mineral which forms igneous rock. Scale: Crystal size 3 x 2 cm. It is found it all of the three rock types, but is most common in intrusive igneous rocks like granite where the crystals look white or pink. Together with their non-metallic luster and typically opaque character, these properties will usually distinguish feldspars from other common non-metallic minerals. Cleavable, granular, massive. A scratch is a permanent line or groove cut into the surface of the material being tested and caution should be taken not to damage a valuable gem. Help on Above, Colville A A , Ribbe P H , American Mineralogist , 53 (1968) p.25-37, The crystal structure of an adularia and a refinement of the structure of, orthoclase, Note: Spencer B, variety adularia, GRapi = 200.97 (Gamma Ray American Petroleum Institute Units) USA & Canada only: else This mineral has a density of about 2.56, and its hardness is 6. Faceted orthoclase gemstones make stunning pendants, rings and earrings. This is a great way of identifying feldspar minerals. Optical Properties : In thin section, orthoclase has low birefringence, moderate relief, and resemblance to quartz. html += printReadyElem.innerHTML; It is a raw material used in the production of glass, ceramic tile, porcelain, dinnerware, bathroom fixtures, and other ceramics. Since orthoclase has a hardness of 6 to 6.5, simply wiping the dust off an orthoclase gemstone can gradually reduce its polish. Out of stock. Color : white, pink, turbid. The feldspar minerals are mixtures of sodium, potassium, and calcium aluminosilicates, and any feldspar may be classed by its percentage of each of these three pure compounds, called end-members.Orthoclase is the potassium-bearing end-member of the system; its symbol is Or.. Orthoclase and the sodium-bearing end-member of the system, albite (sodium aluminosilicate; NaAlSi 3 O 8), … The hardness of Feldspar on Moh's Scale is 6, just like Orthoclase. Orthoclase is not currently known to be treated or enhanced in any way. In addition to all these similarities in physical properties, all feldspar minerals have a vitreous luster that is mostly pearly on cluster faces. It has a Mohs hardness of 6 and has two cleavage planes which occur at right angles to each other. printWin.document.open(); It has a Mohs 6 - 6.5 so is most suitable for collectors or for pendants, earrings and pins. The luster is vitreous, sub-vitreous or resinous. Scratch tests are a common method used to identify mineral hardness relative to Mohs' scale. Potassium feldspar crystals have a hardness score of 6 to on the Mohs Hardness Scale. Find gemstone information by specific locations.