Gemstones, Diamonds, Pearls - Multicolour.com
My Shopping Cart My Account Gem Library
|Welcome to Multicolour.com|Single Stones|Calibrated Stones|Pairs|Mix Lots|Closeouts|Carved Gems|lapidary and gemological tools and supplies|Gem Smart Search|
 Home / Gem Library / Natural Gemstones / Scheelite November 21, 2017  


Natural Scheelite
E-mail this article to a friend

There are 4 Scheelite(s) available at Multicolour.com


Despite its low hardness, scheelite has been faceted as a gemstone for collectors. Its high refractive index and adamantine luster assure bright and surprisingly attractive gemstones. The refractive indices are 1.918 1.934 with a positive sign and a birefringence of .016. Scheelite is extremely dense with an SG that varies between 5.9 to 6.1. The absorption spectrum may show faintly the didymium rare earth spectrum of groups of lines in the yellow and green with a stronger line at 584nm. Scheelite is well known for the strong bright blue fluorescence it exhibits under short wave ultra-violet light. It is practically inert under long wave UV.


Known Facts
Color Key: Yellowish-white, brownish, orange yellow
Refractive Index: 1.918 - 1.937
Chemical Composition: CaWO4
Hardness: 4.5 - 5.0
Density: 5.9 - 6.1
Crystal Group: Tetragonal
Ocurrence: Czechoslovakia; Italy; Switzerland; Finland; Cumberland, Cornwall, England; Santa Cruz, Sonora, Mexico; South Dakota, Conneticut, Colorado, Utah, California, Arizona, USA; New South Wales and Queensland, Australia; Mian Yang, and Ping Wu, Sezhuan, China; Hollinger Mine, Ontario, Canada;

Yellowish to brownish but sometimes almost orange-yellow in color, the calcium tungstate mineral scheelite is an important ore of tungsten. Although most of the world wide production of tungsten comes from the mineral wolframite, scheelite is abundant in the United States and provides the country with most of its supply. Scheelite was named for the discoverer of tungsten, K. W. Scheele, the Swedish chemist who proved the existence of tungsten in the mineral.

Scheelite is a member of the tetragonal system and crystals often show dipyramidal habits that look very much like octahedrons. These pseudo-octahedral crystals are sometimes truncated with minor pyramids, but only on the top and/or bottom points of the crystal; giving evidence of their true symmetry. Other minerals that form pseudo-octahedral crystals similar to scheelite include wardite, anatase and powellite. The crystals of scheelite can look like fluorite octahedrons which can also fluoresce but fluorite has perfect octahedral cleavage and a much lower luster. Massive sheelite has also been misidentified as massive quartz but its strong fluorescence provides conclusive proof of its true identity.

Powellite, CaMoO4, is isostructural with scheelite which is why it forms similar crystals. The two minerals form a series in which the tungsten of scheelite is substituted for by the molybdenum of powellite. Powellite fluoresces a yellow color while scheelite fluoresces a bright blue under short wave ultraviolet light. Since molybdenum can substitute for tungsten, some scheelite specimens will also show a yellow fluorescence.

Many prospectors for scheelite have made good use of scheelite's typically bright blue fluorescence by searching for scheelite deposits at night with ultraviolet lamps. Many old mines have even been reopened after examinations of the mine shafts with ultraviolet lamps which proved that the ore was not yet exhausted.

Associated Minerals include quartz, garnets, vesuvianite, epidote, topaz, schorl, apatite, gold, silver, molybdenite, cassiterite, wolframite and fluorite. The best field indicators are crystal habit, color, density, luster and especially SW fluorescence.


Illustrations
Scheelite Scheelite
Check our Top, Largest, Smallest or Latest Scheelite's.


Scheelite Stats/
Popularity Index: 59972hits
Total Items: 4items
Total Weight: CTS 23.83
Cheapest: USD 116.20
Most Expensive: USD 440.00
Largest: CTS 10.31
Smallest: CTS 3.32
Last Added: 05/27/14 10:10:51

Knowledge Search/
Enter Keywords:
Enter one or more keywords (i.e madagascar sapphires ).

About Gemstones /

Gem Library/
Gems Legend and  Lore Gems Legend and Lore
Some of the latest of ways that gems have been associated with Birthstones and Signs of the Zodiac.
Understanding Gemstones Understanding Gemstones
Learn about Physical and Optical properties, color, clarity and cut of gemstones.
Gems Glossary Gems Glossary
Ever wonder what are "Blemish", "Luster", "Saturation" "Uniformity" or "Mine Run" means?
Reference and  Links Reference and Links
Recommended books and links to Gem, Jewelry&Mineral Magazines, Gem Institutes and Labs.

Book’s Corner/
Buy at Amazon.com DK Handbooks: Gemstones by Cally Hall and Harry Taylor
Price: USD 15.16
"Very good reference book to gems, stones and bones used in jewelry and ornamentations. Easy to use and read..."
see more Multicolour.com recommendations

 Top of Page Need help?  

Gemstones for sale: Alexandrite, Garnet, Diamond, Opal, Spinel, Sapphire, Tourmaline, Tanzanite, Tsavorite,
Gemstones by Category: Calibrated, Carving, Closeout, Mixed Lot, Pair, Rough, Single, Best Sellers or Featured Gemstones.
Gemstone education: Colored Gemstones Guide, Gems Library, Gemstone Treatments, Gemstone Glossary, Gems and Astrology,

A BBB Accredited Business All Transactions secure by Thawte certificate - click here to validate Ebay Power Seller Gem Certification Various Shipping Options Major Credit Cards Accepted

All trademarks and logos shown herein are the property of their respective owners. © Copyright Multicolour.com, 1998-2011. All rights reserved. Use of this site constitutes acceptance of Multicolour.com Return Policy, Privacy Policy and Trading Guarantee. Published and operated by David Wein Ltd. 32 Hollywood Road, Central, Hong Kong Island Hong Kong. Lost? Check site map or resources page.

Site design and maintenance by NetComposite ®.