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Alexandrite

Tsarstone collectors guide

alexandrite natural of photo stone

481. Top Blue Green Alexandrite Oval 2.15cts.
Extremely rare Alexandrite (Chrysoberyl) Oval 2.15cts from India (Deobhog area)
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482. Top Gem 6mm Strong Change Alexandrite 1.19cts.
Rare Alexandrite (Chrysoberyl) Round 1.19cts from India (Deobhog area)
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483. Top Gem Quality Natural Alexandrite 8.66cts.
Extremely rare Alexandrite (Chrysoberyl) Oval 8.66cts from Tanzania (Tunduru)
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484. Transparent
A gemstone permits the pass of electromagnetic radiation through it without distortion so that the object can be seen clearly and distinctive through it, such a quartz crystal. It is a see through effects.
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485. Tsarina rings at Alexandrite discussion forums | Alexandrite guide
Tsarina rings at Alexandrite discussion forums | Alexandrite guide
HTML, 25 Kb, 2009-03-17 14:21:00
/discussion/topic/tsarina-rings-FRM-287
486. Ultramafic
A type of igneous rock characterized by a high content of mafic minerals, particularly olivine, pyroxenes, amphiboles, etc. The silica content is less than 45%.
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487. Ultrasonic cleaning
A device for cleaning dirt and other foreign particles from gemstones and jewelry articles by subjecting them to ultrasonic vibrations immersed in water or other solvent. The articles must be free of stress flaws. Glass lenses and other bodies can be poli
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488. Ultraviolet lamp
A mercury discharched lamp in quartz glass designed to produce ultraviolet light for exciting luminescence in gem minerals specially diamonds. The long-wave lamp is provided with wood's glass filter to emit wavelengths between 400 nm and 300 nm. To obtain
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/chapters/glossary/ultraviolet-lamp.html
489. Ultraviolet microscope
A special magnifying device for investigating the objects are illuminated by ultraviolet light in the range 180 to 400 nm. The resolving power is increased corresponding to the resolution of shorter wavelengths than visible light. It requires special quar
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/chapters/glossary/ultraviolet-microscope.html
490. Useful tool for beginners at Alexandrite discussion forums | Alexandrite guide
Useful tool for beginners at Alexandrite discussion forums | Alexandrite guide
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/discussion/topic/useful-tool-for-beginners-FRM-172
491. Usenet, Google Groups, Alexandrite at Alexandrite discussion forums | Alexandrite guide
Usenet, Google Groups, Alexandrite at Alexandrite discussion forums | Alexandrite guide
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/discussion/topic/usenet-google-groups-alexandrite-FRM-155
492. Vacuum fluorescence display
A miniature cathode ray tube (CRT), which is closet to cover glass and heated cathode made of tungsten wire emits electrons. The electrons are accelerated by positively charged by hexagonal steel and passing through the grid to anodes covered with blue fl
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/chapters/glossary/vacuum-fluorescence-display.html
493. value at Alexandrite discussion forums | Alexandrite guide
value at Alexandrite discussion forums | Alexandrite guide
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494. Vanadium
A very hard, light-gray, ductile, malleable, metallic element of the group V of the Periodic System with the symbol V. It is one of the 8 pigment metals responsible for color in gemstones such as beryl, sapphire (natural or synthetic). Used as a component
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/chapters/glossary/vanadium.html
495. Vanadium Green Chrysoberyl Oval 2.51cts.
Hard to find Chrysoberyl (Chrysoberyl) Oval 2.51cts from Tanzania (Tunduru)
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496. Very modern, sleek Alexandrite ring at Alexandrite discussion forums | Alexandrite guide
Very modern, sleek Alexandrite ring at Alexandrite discussion forums | Alexandrite guide
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497. Vintage alexandrite ring at Alexandrite discussion forums | Alexandrite guide
Vintage alexandrite ring at Alexandrite discussion forums | Alexandrite guide
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498. Volcanic glass
A solid volcanic natural form of glass (rock) produced by sudden cooling and solidification of viscous lava before crystallization can take place, such as obsidian, pitchstone or other glassy masses. Obsidian is used for tumbled gems, ornamental objects,
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/chapters/glossary/volcanic-glass.html
499. Volcanic rock
Generally a fine crystalline or glassy igneous rock, which is formed by the solidification of molten magma or lava on the Earth's surface during volcanic action. Such as basalt, obsidian, etc.
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/chapters/glossary/volcanic-rock.html
500. Water of crystallization
Water molecules, which have been chemically combined in certain crystals or hydrated salts, which are given off when the crystals are heated.
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501. Wave form of light
The pictorial graphical representation of the shape of a wave obtained by plotting the values of the periodic quantity against the time.
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502. Wavelength
The distance between two points having the same phase on the following or preceding wave. The wavelength of electromagnetic radiation is equal to the velocity of the wave divided by its frequency =c/v. It is measured in nanometers unit.
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503. Weathering
A natural geological description for disintegration and decomposition of rocks and minerals as consequent exposure to atmospheric agents at or near the Earth's surface such as chemical action of air, rainwater, frost, insolation, bacteria, plants, and mec
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504. Website feedback at Alexandrite discussion forums | Alexandrite guide
Website feedback at Alexandrite discussion forums | Alexandrite guide
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/discussion/topic/website-feedback-FRM-157
505. Weight of gemstones and precious metals
A standard mass. The unit of weight of gemstones since 1913, is the international metric carat or decimally of them in points.
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506. What gemstones change color like alexandrite? at Alexandrite discussion forums | Alexandrite guide
What gemstones change color like alexandrite? at Alexandrite discussion forums | Alexandrite guide
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/discussion/topic/what-gemstones-change-color-like-alexandrite-FRM-282
507. What are the most common colors of alexandrite?
Unfortunately, most alexandrites show either a nice color in daylight or an attractive color under incandescent light. Rarely are both colors bright and vivid and often stones that change to bright red under incandescent light are only brown or almost bla
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508. What causes the cat's-eye effect in chrysoberyl?
The cat's-eye effect is caused by the reflection of light off of minute, parallel, needle-like rutile crystals or hollow tubes within the stone. Cat's eye inclusions are aligned parallel to the crystallographic axis and the stones are always cut as caboch
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509. What do I need to check before purchasing alexandrite gemstone?
First and foremost, we need to look at the quality and strength of the color change. A strong change where the colors are bright and attractive under any kind of light is most desirable. Many stones are either a beautiful green in daylight or a nice pinki
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510. What is the best way to clean and take care of alexandrites?
With a hardness of 8.5, Alexandrite is a tough, hard, and durable gemstone that doesn't require any special attention. Still, even the hardest gemstones can shatter with a single well-placed blow so caution is always a good idea. Washing dishes with your
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511. What is the difference between cat's eye and alexandrite?
Cat's eye is the popular name for an optical effect known as chatoyancy in the gemological nomenclature. Microscopic needle-like inclusions inside the stone reflect a streak of light that appears to open and close as the stone is rotated -- hence the eye
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512. What is the difference between chrysoberyl and alexandrite?
Chrysoberyl is the species name and Alexandrite is the variety name. Alexandrite is that variety of chrysoberyl that changes color as a function of the light source; green in daylight and red under incandescent light.
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513. What is the difference between chrysoberyl and alexandrite? at Alexandrite discussion forums | Alexandrite guide
What is the difference between chrysoberyl and alexandrite? at Alexandrite discussion forums | Alexandrite guide
HTML, 25 Kb, 2009-03-19 22:15:42
/discussion/topic/what-is-the-difference-between-chrysoberyl-and-ale-FRM-302
514. What is the june gemstone? at Alexandrite discussion forums | Alexandrite guide
What is the june gemstone? at Alexandrite discussion forums | Alexandrite guide
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/discussion/topic/what-is-the-june-gemstone-FRM-337
515. What makes natural alexandrite so expensive?
Alexandrite is an expensive gemstone because it so rare and production has always been limited. For years, the only source for alexandrite was Russia. In the last 20 or 30 years several new discoveries of alexandrite have been reported but production of s
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516. What's the difference between a Valuation and Appraisal? at Alexandrite discussion forums | Alexandrite guide
What's the difference between a Valuation and Appraisal? at Alexandrite discussion forums | Alexandrite guide
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517. Where can I buy natural alexandrite gemstones?
Fine alexandrites or alexandrite jewelry can be purchased from jewelers specializing in colored gemstones, at trade shows, from TV sellers, at high end jewelry auctions, or online from websites specialized in alexandrite. You would be unlikely to find a h
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518. Where can I test and appraise my alexandrite?
The most well known gemological laboratories are listed below and all of them are equipped to test alexandrite. Most gemological laboratories only identify gemstones, they do not appraise them.
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519. Where do the best alexandrite gemstones come from?
Although Russian alexandrites have the most historical value, fine stones are occasionally available from deposits in Brazil, India, Tanzania, Madagascar, and Sri Lanka. Unfortunately, there has been little production of alexandrites from any deposit in r
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520. Why do you love alexandrite? at Alexandrite discussion forums | Alexandrite guide
Why do you love alexandrite? at Alexandrite discussion forums | Alexandrite guide
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521. Why does alexandrite appear to change color in sunlight and artificial light?
Alexandrite is a trichroic gemstone which absorbs and reflects light differently in each of its three optical directions. Spectroscopic analysis reveals a different absorption spectrum for each of the three optical directions. The differences in absorptio
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522. Why is natural alexandrite better than synthetic alexandrite?
Natural alexandrite is not better than synthetic alexandrite but natural alexandrite is very rare and uncommon in modern jewelry because it is hardly ever available and because it is too expensive for the general public to buy. Even lower quality more inc
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523. X-ray
The produced wavelengths of X-rays according to the electromagnetic theory of light consisting of continuous band of wavelengths, which are a mixture of all wavelengths. Depends on the used voltage of apparatus, which is know as white X-ray radiation or g
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524. X-ray crystal spectrometer
A device to obtain an X-ray spectrum for determining the wavelength of its chemical consistent. Each element, when irradiated by electrons, emits X-ray of several characteristic frequencies the line spectrum depending on the atomic number.
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525. X-ray filters
To generate monochromatic X-rays or line spectrums only one wavelength used is a suitable selective filter made of very thin layers of metal elements. There have one or two atomic numbers lower than the target metal such as nickel with atomic number 28 us
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526. X-ray fluorescence
If a crystal is irradiated by an intense X-ray or gamma-ray beam, this includes the substance to emit its visible characteristic secondary X-ray line spectra of a longer wavelength, which is known as X-ray fluorescence. It is a nondestructive method. Used
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/chapters/glossary/x-ray-fluorescence.html
527. X-ray spectrum
Several characteristic lines of the spectrum of X-ray, which are emitted by a bombardment of material with electrons such as curved dark lines on the films produced by X-ray method of powder diffraction of stone or minerals.
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528. Y-axis
One of the 3 optic axes and intermediate axis in biaxial crystal.
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529. Yehuda treatment
A colorless glass-like material used as an impregnation or filling agent to improve the appearance and reduce the visibility of inclusions in stones such as diamonds and emeralds.
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530. Yellow chrysoberyl
Yellow greenish to light yellow or brown chrysoberyl, which contains ferric iron as an impurity. Has an absorption spectrum band at first part of the violet at 444 nm, which can be seen in some chrysoberyl cat's-eye.
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/chapters/glossary/yellow-chrysoberyl.html
531. Young-Helmholtz theory of color vision
The theory that the eye contains three different groups of retinal fibers (cones) with maximum response to three primary colors to red-yellow, green, and blue violet, which are parts of the spectrum.
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/chapters/glossary/young-helmholtz-theory-of-color-vision.html
532. Yttrium
A dark gray, silvery luster, rare earth metallic element of the Periodic System with the symbol Y. Flammable when powder from. Used in alloys and as a metal deoxidizer.
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/chapters/glossary/yttrium.html
533. Zandrite at Alexandrite discussion forums | Alexandrite guide
Zandrite at Alexandrite discussion forums | Alexandrite guide
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/discussion/post/zandrite-FRM-324-00001
534. Zenhokyo
Leading gemmological educational institution in Japan has been providing professional education in the field for the past 30 years. Zenhokyo Laboratory is equipped with the most professional and advanced testing devices and systems, including inductive
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/directory/laboratories/zenhokyo-wdd-003-00012.html
535. Zimbabwe at Alexandrite discussion forums | Alexandrite guide
Zimbabwe at Alexandrite discussion forums | Alexandrite guide
HTML, 25 Kb, 2007-04-30 10:24:42
/discussion/topic/zimbabwe-FRM-163
536. Zimbabwean alexandrite, Girdlestone Farm
Information about Zimbabwean alexandrite findings and mining in Girdlestone Farm, Zimbabwe.
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/localities/alexandrite-locality-zimbabwe-masvingo-girdlestone-farm.html
537. Zonary growth
Zonary growing of crystals bounded by plane crystal faces, which occur by slight variation in the composition of a crystal due to separation or interruptions of the crystal phases during growth.
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538. Zone
A group of crystal faced intersection, which are parallel to a common line.
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539. Zone axis
A line runs through the center of a crystal, to which all faces of a given zone are parallel.
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540. Zone of crystal faces
In crystallography a characteristic feature of a serie faces of a crystal where those intersection lines with each other are all parallel.
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541. Zoning
The straight, parallel growth-lines in the internal structure of a gemstone with definite angles, usually seen in some stones, which occur by slightly variation in the chemical composition within the crystal due to separation or interruptions of the cryst
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/chapters/glossary/zoning.html
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