XENOTIME MINERAL FACTS Nevada Turquoise gem stones
The Gem and Mineral Collector's Photo Gallery by Nevada Outback

.

Xenotime Mineral Facts:

Chemical Formula: YPO4
Y
ttrium phosphate. Essentially a yttrium phosphate, but usually contains erbium and in some cases cerium, various rare earths, silicon and thorium.

Colors: Yellowish, pink, gray or reddish brown.
Its streak is a pale shade of the same color. Xenotime is also dichroic.

Hardness: 4.5

Density: 4.5 to 5.1

Cleavage: Perfect cleavage on (100).

Crystallography: Tetragonal
Crystal forms resemble those of zircon. Its crystals are octahedral or prismatic. Also found in rolled alluvial grains.

Luster:Vitreous to resinous luster. It is translucent to opaque. 

Optics: (Refractive Index):  = e= 1.81, w = 1.72

Orange Xenotime Crystal

Orange Xenotime Crystal


Composition, Structure and Associated Minerals:
Xenotime is a rare mineral which occurs, like monazite, as an accessory constituent in granite, gneiss and pegmatite veins. Found as rolled grains in the stream sands, particularly in Brazil.
Although xenotime may contain significant amounts of radioactive elements like thorium or uranium, however the mineral does not degrade and become metamict like sphene or zircon would. 

Identification and Diagnostics
Before the blowpipe, infusible alone and without fluxes. Xenotime is infusible, insoluble in acids and with difficulty soluble in molten microcosmic salt. It is distinguished from zircon by its cleavage and inferior hardness. Insoluble in hydrochloric acid. After fusion with sodium carbonate, dissolve in nitric acid and add solution to excess of ammonium molybdate solution. A yellow precipitate forms (positive test for the presence of phosphate). A potential confusion of xenotime with zircon (ZrSiO4),may occur because of its similar tetragonal crystal structure, its vitreous luster, and the typical low level radioactivity of both minerals. Xenotime has an inferior hardness and will give a positive test for phosphates which zircon will not. A variety of xenotime containing a small percentage of sulfates is known as hussakite.  

Xenotime rare earth ore

Xenotime Crystal

Occurrence, Localities and Origins:
The mineral occurs in pegmatite veins, as a minor accessory mineral in granites and crystalline metamorphic rocks. It is also found as a heavy residual mineral in the sands of streams. It is found in pegmatite veins at Hittero, Moss, and other places in Norway; at Ytterby, Sweden; in the granites of Minas Geraes, Brazil, the Khyber area of Pakistan. It is found with the residual heavy minerals in the placer gold nugget washings at Clarksville, Georgia, and many places in North Carolina. It is also found in pegmatite veins in Alexander County in the same State. It occurs in schist rocks in Music Valley in southern California and in Colorado. It is recovered as a minor ore mineral in many heavy sand recovery operations which are worked primarily for monazite and other elements in Brazil, India, South Africa and Australia. It is also recovered as an alluvial heavy material in association with Malaysian casseterite tin mining. Xenotime is a minor rare earth ore mineral, being rich in the heavy lanthanide elements, especially the even numbered lanthanides. Like monazite, the mineral must be chemically dissolved to separate the various rare earth elements.

Return to the Mineral Collectors Information Page

 

 

Please note that the author, Chris Ralph, retains all copyrights to this entire document and it may not be reproduced, quoted or copied without permission.

Turq_nev_6b.gif (5020 bytes)

NEVADA OUTBACK GEMS TURQUOISE AND JEWELRY

Nevada Outback Gems

Find out more by checking out All of our links below:

View our Contemporary Turquoise Jewelry - Wearable Artwork! View our Unique Gem Quality Turquoise Cabochons
Premium Jewelry, with Gemstones of all types Top Quality Loose Gemstones - Gemstones of all types
Rare Crystals and Gemstone Rough, all types Our Free Colored Gemstone Information Encyclopedia
Chris' Gold Prospecting Encyclopedia Take a virtual tour of our Nevada Turquoise mines
Miners Reference Pages         California Gold Rush Stories More Info about Turquoise, the Beautiful Gem
Metal Detecting with the MXT Metal Detector Nevada Outback Gems Homepage
Build Your Own Mining Equipment Investing in Gold and Precious Metals
Basic Placer Mining More information about us - Nevada Outback Gems
Locations to Prospect for Gold The Rockhound's Corner Nevada Outback Library and Bookstore - Learn more!
Chris's Prospecting Adventures About Nevada Turquoise More Info about Gem Cutting Tanzanite Jewelry
Nevada Outback Gems Site Map Make Your Own Jewelry Buy Safely on EBay: avoid fraud and scam artists