Origin of Pleochroism in Erythrite.

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SeriesCanada Mines Branch Reprint Series -- 75
ContributionsFaye, G.H., Nickel, E.H.
ID Numbers
Open LibraryOL21896155M

Erythrite crystallizes in the monoclinic system and forms prismatic crystals. The color is crimson to pink and occurs as a secondary coating known as cobalt bloom on cobalt arsenide minerals.

Well-formed crystals are rare, with most of the mineral manifesting in crusts or small reniform ry: Arsenate mineral, Vivianite group. THE ORIGIN OF PTEOCHROISM IN ERYTHRITE G. FAYE* aNo E. NICKELT Ansrnacr optical absorption measurements show that the pleochroism of erythrite is due to variations in the main absorption envelope in the to 60Gmp refion as crystallo-graphically oriented sections are rotated in linearly polarized iigt tl tfru absorption.

Erythrite was first described in for an occurrence in Grube Daniel, Schneeberg, Saxony, [3] and takes its name from the Greek έρυθρος (erythros), meaning red. [2] Historically, erythrite itself has not been an economically important mineral, but the prospector may use it as a guide to associated cobalt and native silver.

The most common minerals on earth Information for Educators Mindat Articles The Elements Books & Magazines. Faye and E. Nickel () The origin of pleochroism in erythrite. Although the colour and pleochroism of blue kyanite has been attributed to the presence of Ti (super 3+) by previous workers, the present study of the polarized absorption spectra of such kyanite indicates that Fe (super 2+) Fe (super 3+) charge transfer accounts more readily for the optical by: Pleochroism.

Pleochroism is the term used to describe the color variation for destructive interference with the polarization direction of the light, which depends on the orientation of the material in the light path and is a characteristic of anisotropic materials only. From: Optical Thin Films and Coatings, Related terms: Asbestos.

Pleochroism definition: a property of certain crystals of absorbing light to an extent that depends on the | Meaning, pronunciation, translations and examples. Pleochroism is an extremely useful tool in mineralogy and gemology for mineral and gem identification, since the number of colors visible from different angles can identify the possible crystalline structure of a gemstone or mineral and therefore help to classify it.

Minerals that are otherwise very similar often have very different pleochroic. Pleochroism (z): red. Calculated Properties of Erythrite: Electron Density: Bulk Density (Electron Density)= gm/cc note: Specific Gravity of Erythrite = gm/cc.

Fermion Index: Fermion Index = Boson Index = Photoelectric: PE Erythrite = barns/electron U=PE Erythrite x rElectron Density= barns/cc.

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Erythrite Co3(AsO4)2• 8H2O c Mineral Origin of Pleochroism in Erythrite. book Publishing, version 1 Crystal Data: Monoclinic. Point Group: 2/m. Rarely well crystallized, typically flattened on [], may be elongated prismatic and striated k [], with many forms, to 10 cm. In radial or stellate aggregates, fibrous, drusy; usually powdery, massive.

Pleochroism is caused by differing absorption of light rays in doubly refractive crystals. Thus, no singly refractive gemstone can exhibit pleochroism (diamond, spinel and garnet are the best-known singly refractive gems).Pleochroism is also absent in amorphous gems (those that have no definite crystal structure), opaque stones, colorless stones and most gems that are translucent rather.

Pleochroism in Tourmaline. Tourmaline is one of the most strongly pleochroic gems. Indeed, its pleochroism is so distinct that it was once used to manufacture crude polariscopes (“tourmaline tongs”).

Because of its strong pleochroism, the orientation of cut stones is extremely important (figure 8). An optical absorption study of the origin of colour and pleochroism in pink and brown tourmalines. Erythrite is a secondary mineral in cobalt-bearing deposits. Erythrite occurs as a secondary mineral in the oxide zone of Co–Ni–As bearing mineral deposits.

It occurs in association with cobaltite, skutterudite, symplesite, roselite-beta, scorodite, pharmacosiderite, adamite, morenosite, retgersite, and malachite. Tourmaline Sources. Brazil has been the world's leading source of tourmaline for nearly years. In the s Portuguese explorers obtained green and blue tourmaline from indigenous people and from panning streams in search of thought that these colorful stones were emeralds and sapphires and sent them back to Portugal, where they were cut into gems and used to make jewelry for.

Pleochroism definition is - the property of a crystal of showing different colors when viewed by light polarized in different directions. Pleochroic definition, (of a biaxial crystal) characterized by pleochroism. See more. Pleochroism (x): pale pink. Pleochroism (y): pale violet. Pleochroism (z): red.

Calculated Properties of Erythrite: Electron Density: Bulk Density (Electron Density)= gm/cc note: Specific Gravity of Erythrite = gm/cc. Fermion Index: Fermion Index = Boson Index =. ‘In this book Joly also discussed the measurement of the radioactivity of rocks and the origin of pleochroic haloes.’ Origin.

Mid 19th century from pleo-‘more’ + khrōs ‘color’+ -ic.

Description Origin of Pleochroism in Erythrite. EPUB

Word of the day. perishing / ˈpɛrɪʃɪŋ / adjective. See definitions & examples. Some band-gap semiconductor minerals are listed in Table 6. Semiconducting ore minerals are the subject of a book by Shuey (). Impurities in semiconductors Medium- and large-band-gap semiconductors do not conduct electricity at room temperature when pure, since the ambient excitation is insufficient to bridge the band-gap.

Erythrite definition, a mineral, hydrous cobalt arsenate, Co3As2O8⋅8H2O, occurring as a powdery, usually red incrustation on cobalt minerals; cobalt bloom. See more. Pleochroism, (from Greek pleiōn, “more,” and chrōs, “colour”), in optics, the selective absorption in crystals of light vibrating in different planes.

Pleochroism is the general term for both dichroism, which is found in uniaxial crystals (crystals with a single optic axis), and trichroism, found. Pleochroism in Tanzanite. Tanzanite is noted for its remarkably strong trichroism, appearing alternately blue, violet and burgundy depending on crystal orientation.

It is named after its country of origin, Tanzania (in central East Africa) Erythrite Erythrite or red cobalt is a secondary hydrated cobalt arsenate mineral with the formula.

The phenomenon of pleochroism in doubly refractive (DR) gemstones is described, as it relates to overall color appearance in the context of faceted gems. With strongly pleochroic gems, pleochroism can be seen in faceted gems, even if the table facet is oriented perpendicular to an optic axis.

an understanding of the origin of colour and pleochroism in ferro-magnesian silicates (Faye,a; Faye, Manning and Nickel, ). It was shown, for example, that the pleochroism of phlogopite, biotite and chlorite with normal schemes can be directly related to the electronic interaction of Fe2+ and other ions in the octahedral layer.

(1) Hudson Bay mine, Canada; after deduction of erythrite–annabergite 69%, corresponds to Fe(AsO4) • H2O.(2) Fe3(AsO4)2(OH)3 • 5H2O. Occurrence: In the oxidized zone of a Co–Ni sulfide deposit (Hudson Bay mine, Canada); in the oxidized zone of a polymetallic hydrothermal ore deposit (Neubulach, Germany).

Pleochroism is the change of color in colored anistropic (double refractive) gemstones when viewed from different directions or when viewed though plane polarized light. When light enters such a gemstone, it will be split into two rays that are perpendicular polarized. 8 people chose this as the best definition of pleochroism: The property possessed by See the dictionary meaning, pronunciation, and sentence examples.

“The origin of pleochroism in erythrite” (PDF). The Canadian Mineralogist 9: – Wikimedia Commons có thêm hình ảnh và phương tiện truyền tải về Erythrit. Pleochroism in gemstones by Yuman Hussain Scientific explanation of pleochronism which is an ability of the stone to absorb different wavelengths of light displaying brilliant colors when viewed from different directions.

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What is Pleochroism Have you ever wondered about the color of a gemstone. How and from where. Thus, a consequence of pleochroism is that stones look different colors in different orientations.

Note that not all stones show pleochroism! Note that the information below further illustrates the concept of pleochroism by providing examples but the information is NOT required for students of EPS 2.

S,D,W,VW = strong, distinct, weak, very weak.The surface structure of the matrix is beautifully documented and the erythrite is breathtaking! Thanks for posting! If possible, I would like to learn about some technical details, because I like to learn from the best possible examples.The following is a list of Strong Pleochroism gems and minerals listed in our database.

Click the pictures to get full data, click the X to remove the gem from the list. Indicolite: Indicolite is the blue sodium-rich variety of Tourmaline, and may come in all shades of blue, from light-blue, violet-blue to .