|Item # SCHE03146588
Rare Specimen of Euhedral
|Rare Multiple pseudo-octahedral euhedral crystals, that measure up to 25mm per
side, with Muscovite. Excellent specimen!! Excellent Fluorescence!! This superb
specimen is from our personal collection. It was obtained in 2004 from a mineral
dealer in Tucson, Arizona and has been on display in our cabinet. It is from the
Mianyang Mine, Mianyang City, Mianyang Prefecture, Sichuan Province, China.
This specimen weighs 0.36 lb (162g) and measures 1.9 x 1.9 x 1.3 inches
(4.9 x 4.9 x 3.3cm)
|The Scheelite-Powellite Series is an uncommon secondary mineral, typically formed in the oxidation zones
of molybdenum-bearing hydrothermal deposits.
Scheelite is Calcium tungstate, an important ore of tungsten which is a strategically important metal.
Scheelite is named for the discoverer of tungsten, Karl W. Scheele. Scheelite is a “Must Have” for serious
mineral collectors. It forms perfect tetragonal dipyramidal crystals that look very much like octahedrons.
These pseudo-octahedral crystals are sometimes truncated with minor pyramids, but only on the top or
bottom points of the crystal. Other minerals that form pseudo-octahedral crystals similar to Scheelite include
Wardite, Anatase and Powellite.
Powellite is associated with Scheelite and it forms similar crystals. The two minerals differ in that Scheelite
contains tungsten while Powellite contains molybdenum. Powellite fluoresces yellow while Scheelite
fluoresces a bright blue under short wave ultraviolet light. Scheelite has a waxy translucent
appearance. Many rockhounds and prospectors looking for Scheelite have made excellent finds by
searching old mines and trailings at night with SW Ultra-Violet lights. The bright blue fluorescence of
Scheelite is unmistakable!
Powellite is a calcium molybdate mineral, and may occur as well-formed coarse sized granular crystals. It
generally occurs as Anhedral to Subhedral crystals in matrix. (A rock with an Anhedral texture is composed
of mineral grains that have no well-formed crystal faces. An intermediate texture with some crystal face
formation is termed Subhedral.) Euhedral crystals are those that are well-formed with sharp, easily
Euhedral is a morphological term referring to grains in igneous rocks which have a regular crystallographic
shape. Euhedral forms are developed when a crystal grows freely in a melt and is uninhibited by the
presence of any surrounding crystals. (A melt is the liquid part of silicate magma. Magma may consist solely
of melt or of melt and suspended crystals) the shape of the growing crystals will thus be controlled by their
own natural crystallographic form.
Anhedral is a morphological term referring to grains in igneous rocks which have no regular crystalline
shape. Anhedral forms are developed when a crystal's free growth in a melt is inhibited by the presence of
surrounding crystals. The shape of the growing crystal is thus controlled by the arrangement and orientation
of the surrounding pre-existing crystals.
|Scheelite under SW
Ultra Violet Light
|Item # SCHE03143465
265g Fluorescent Scheelite
|Large pseudo-octahedral euhedral crystals, that measure up
to 44mm per side, on Quartz and Muscovite. It is from the
Xuebaoding Mines,Sichuan Province, China. Excellent
daylight and fluorescent specimen!
This specimen weighs 9.3 oz or 0.58 lb (265g)
and measures 2.7 x 2.5 x 1.6 inches
(6.8 x 6.4 x 4.2cm)
|Scheelite under SW Ultra Violet Light
|Item # SCHE03142562
136g Fluorescent Scheelite
|One large pseudo-octahedral euhedral crystal, that measures
up to 25mm per side, on attractive Quartz and Muscovite. It is
from the Sichuan Province, China. Very nice daylight and
fluorescent specimen! Broken edges are from extraction.
This specimen weighs 4.7 oz or 0.3 lb (136g)
and measures 1.9 x 1.8 x 1.1 inches
(4.9 x 4.5 x 2.8cm)
|Scheelite under SW Ultra Violet Light
|Item # POWL031459931
Powellite from India
|Extremely rare and unique Powellite specimen from Nashik.
Nashik is a city in the state of Maharashtra in Western India. This
specimen is from our personal collection. We obtained it in 1998
from Wally Marks at the Highway 50&95 Rock Shop in Fallon,
Nevada during one of our trips to Wonderstone Mountain.
This very unique piece has two distinctly different sides. The top
right photo shows the unique coarse crystal habit of two large
Euhedral crystal formations which are twinned. The top left photo
shows the other side which displays both Anhedral and
Subhedral growth patterns, almost trying to achieve Euhedral
status...avery special specimen of Powellite which is an excellent
daylight and fluorescent display piece.
This specimen weighs 4.3 oz or 0.27 lb (124g)
and measures 2.1 x 2 x 1.2 inches
(5.3 x 5.2 x 3.2cm)
|Powellite under SW Ultra Violet Light