Musgravite
Iwas unable to find allot of information on this very rare gemstone.
The big question that poped up allot is " Is it Musgravite or Taaffeite speical test must be used to tell these two gems about.
If you are like me you love learn about Gemstones.
In mineralogy, the
name Musgravite refers to the mineral called Magnesiotaaffeite-6N’3S. It
crystallizes in the trigonal system.
The closely-related Magnesiotaaffeite, which crystallizes in
the hexagonal system, is known in mineralogy as Magnesiotaaffeite-2N’2S.
Together, they are both part of the Taaffeite group.
Musgravite, described as a 'Rarity among the rare,' is a
mineral, very similar to Taafeite in chemical composition.
It is so rare that
in 2005, there were only eight gem quality Musgravites in the world. Price per
carat is around $35000.
The rare gems taaffeite and musgravite have lately become
more popular among collectors. Due to their similar chemical
compositions
and crystal structures, their main gemmological properties
overlap
and so sophisticated measurement techniques such as
quantitative
chemical analysis, Raman spectroscopy or X-ray powder or
single crystal
diffraction are needed for their identification. This study
describes
an EDXRF instrument used as single-crystal X-ray diffraction
apparatus
and the technique to identify taaffeite and musgravite in a
relatively
conclusive procedure. A special rotating and tilting stage
has been
constructed to non-destructively determine the differences
in diffraction
pattern based on the different symmetries (trigonal and
hexagonal),
unit cell dimensions and space groups of taaffeite and
musgravite.
Taaffeite and musgravite from Sri
Lanka, Myanmar and Tanzania are rare
gemstones that are popular among
collectors Gem-quality taaffeite and musgravite
are both transparent,
commonly with red, purple, blue, violet, grey or very dark
colours. Taaffeite
(BeMg3Al8O16) shows a wider range of colors (which are due
to high amounts
of chromium and iron) than musgravite (BeMg2Al6O12) which has only been
found as purplish grey, greenish grey, greyish blue, and dark
stones to date.
These two mineral species, belonging to the same mineral
group taaffeite, have
very similar chemical compositions and crystal structures
and their gemmological
properties are so similar that they cannot be distinguished
using standard
gemmological identification tests.
Musgravite is one of rare gemstones that have been sought
these years for the collection at GAAJ laboratory. This gem material is known
to be very difficult to be distinguished from taaffeite, which is also a rare variety,
and its identification methods needed to be established. We were fortunate to
obtain the samples that were said to be musgravite this time, and this,
together with analysis on many pieces of taaffeite, lead us to a conclusion
that both materials can be assuredly distinguished from each other.
Musgravite is a
silicate mineral whose main ingredients are beryllium (Be), magnesium (Mg) and
aluminium (Al), and belongs to the same mineral group as taaffeite. Both gems
had been thought polytype (crystals possessing layered structure; each of the
structure is the
same but their cycle along the layering direction is
different), however, from studies to date they are now assumed independent
varieties that have different chemical composition and crystal structure.
It was named ‘musgravite’after
the area Musgrave in Australia from where the material was first found. The
musgravite was later found also in Greenland and Madagascar, but neither of
them produces gem quality material. Two pieces of faceted gem-quality
musgravite from Sri Lanka were reported firstly in 1993. Several reports of
identifying gem-quality musgravite followed that, but the number of identified
musgravite only reaches to eight in total so far, and most of them are less
than 1 carat in size. No one, to the author’s knowledge, was reportedly
identified in Japan.
One piece of the
sample we obtained this time as a musgravite, together with 84 faceted pieces
requested by our client to be identified as taaffeite or musgravite, were
subjected to standard gemmological tests, UV-visible spectrophotometry and
Raman spectral analysis, and 57 pieces of them were tested semi-quantitative
chemical analysis by EDXRF. Two pieces of them were further tested by X-ray
powder diffraction analysis. The results revealed that combination of
UV-visible spectral analysis, Raman spectroscopy and semi-quantitative chemical
analysis by EDXRF can identify musgravite non-destructively and accurately. The
number of musgravite identified by our method this time was 11 pieces,
including a piece of 4.5ct (the largest piece in the world to the author’s
knowledge).
Technical report on
identification of musgravite and taaffeite was addressed at annual
meeting of
the Gemmological Society of Japan in 2006 that was held at Kobe Design
University on 22nd July.
Musgravite – $6,000/carat
Discovered in 1967 in the Musgrave mountains of Australia
this gemstone occurs in a few colors, most notably green and violet.
It is likely that a small part of taaffeite on the market
today is actually musgravite, as it is extremely hard to differentiate the two.
In the early 2000′s only a handful of cut gemstones existed.
In the last few years it has been found in a number of other places, including
Madagascar and Tanzania.
However, gemstone quality musgravite is still exceedingly
rare. High quality greenish musgravite sells for $2,000-3,000 per carat, while
violet stones are even more expensive at around $6,000 per carat.
If you one has more information on this rare gem please let me know.
Thank you for viewing The Wonderful World of Gemstones"
i have some gems that show similar colours as taafeite. they wer dmined by grandfather in 1980's and was kept aside. how to know if they are taafeites?
ReplyDeletehello Mr Jordan, Please give me your contact mobile number
ReplyDeletehi....Mr.Jordan,i'm doing a gem business in Sri lanka.first of all it was my hobby.i'm really interested about rare stones.i have a good collection of spinel.and with my knowledge there are some stones which closed to taafeites or Musgravite..here my email...gayan.ludwick@gmail.com...i'm keep searching of rare stones please be kind to reapply...i will take certificates of those which should be rare...
ReplyDeleteHi brother i have one musgravite 6.57ct GIT certificate have clour violet.
DeleteHallo mein liber bestter freund ...mein name ist hafid & komme aus marokko (seggengen) meine firma wahr 26 jare fertreten in indien---jetzt ist sie zu -weggen ferlusste in marok.meine alte firmen communen haben noch seltene steine 1-mausgravit-2-wittelsbacher-3-gross mongoul-&&&..ich möchtte sie erst ferkauffen wenn alle auf ihren modernen neuen schliff angepastt werden ..zum ferkauf an Singapore. ...wenn jemand einen wittelsbacher&gross mongoul ...kauffen möchtte ...muss in aus seinem allten rossen schliff -in einem heutigem standart um schleiffen?? Danke ihnen seher seher ..liebe sammler von mineralienrohstoffe aus der ganzen weld
DeleteI ve some of sample of musgravite raw if any one interested then plz email me or add my WhatsApp no +91 9531385545, for sample of image there, good luck.
ReplyDeleteHi
DeleteHi
DeleteI have rare gemstones
DeleteHi.very good article
ReplyDeleteI had Musgravite Crystal of type Merit Brnukete(Meerebs) Dark purplish Violet net Weigh about 250 CTS. & Padparadscha Translucent net weigh about 750 CTS.
ReplyDeleteI have Taaffeite or Musgravite several gems. Its refraction value is 1.73 and double refraction checked by Dichroscope. My email---gishanstarlight@gmail.com
ReplyDelete