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Euclase

Posted by Gabriel  
Gabriel
Euclase
July 23, 2012 09:01PM
Hi,

I have this euclase but no clue about how much that specimen worth.

Any guess?

Tks!

Gabriel




Gabriel
Re: Euclase
July 23, 2012 09:05PM
Sorry guys, I forgot the info:

Weight = 65.8gr
Size = 34x34x30mm

Tks

Gabriel
Re: Euclase
July 24, 2012 12:18AM
GABRIEL First and most importantly, I really don't know much about euclase, but I have seen many moderate and hi quality crystals; this is not one of them. Assuming what you really have is euclase, because to me it is just looks like a small dirty off white partially translucent rock, it would only be worth what anyone might offer you. It would help if you had paperwork about it and where it is from etc. If you could get it faceted into a gemstone that would also help. If not, maybe just a few bucks. Hopefully someone out there has better news for you. CHEERS.........BOB
Gabriel
Re: Euclase
July 24, 2012 02:00AM
Hi Bob,

yes I know. ...
This one could be more translucent.
The pic do not help very much because of the natural light that makes the stone blur totally, but it's an euclase for sure.

Tks for your words.
Of course that I expecte a little more than a few bucks : )

Try to cut and see what appears is a good option.

Tks,

Gabriel
avatar Re: Euclase
July 24, 2012 03:55AM
Looks more like topaz or maybe beryl, instead of euclase.
avatar Re: Euclase
July 24, 2012 04:28AM
    
Sorry Gabriel I agree with Steve, from these photos the crystal system looks more hexagonal like beryl rather than monoclinic for euclase. You could try a specific gravity test to narrow it down if you don't want to test hardness and scratch the crystal, both topaz and beryl would be harder than euclase.

I also agree with Bob. Since it is broken and has no termination the value would be significantly reduced and would be better used for cutting.

That's probaby not the answer you wanted to hear but that's the reality.

If you want to see nice euclase crystals to compare just check out the gallery.

regards,
stephanie smiling smiley
avatar Re: Euclase
July 24, 2012 10:48AM
It does not appear to be transparent enough to gut a gem stone out of it, and given the broken nature of the crystal I would be surprised if anyone would pay you more than $20 for the specimen.

Rock Currier
Crystals not pistols.
Re: Euclase
July 27, 2012 10:24PM
I have seen euclase pseudomorph after beryl. What is the origin of the specimen?
avatar Re: Euclase
August 01, 2012 06:03PM
Stephanie Martin Wrote:
-------------------------------------------------------
> Sorry Gabriel I agree with Steve, from these
> photos the crystal system looks more hexagonal
> like beryl rather than monoclinic for euclase. You
> could try a specific gravity test to narrow it
> down if you don't want to test hardness and
> scratch the crystal, both topaz and beryl would be
> harder than euclase.
>
> If you want to see nice euclase crystals to
> compare just check out the gallery.
>
Weeellll.... heres another one of what I think is Euclase going (not quite) hexagonal. It's reportedly from Parelhas, Brazil. Note that the blue coloration in the xtl is associated only with two opposed prism faces. Not too that the etch tubes do not seem to align with any hexagonal axis.I really ought to have another session with this little stone; there's more to tease out of it yet, I think.


Here's another view. The temination is three sided and somewhat striated, more crudely than the sides of the xtl which are finely strated. All striations run on a longitudinal axis. The opposite end of this xtl is broken with some secondary small xtl growth on it that warrants closer examination.


The SG is 3.07 which is good for Euclase but not for transparent Beryl. Monoclinic having another nightmare?
avatar Re: Euclase
August 02, 2012 09:30AM
This appears to certainly be a picture of a Euclase crystal. The blue stripe parallel to the prism makes it pretty definite.

Rock Currier
Crystals not pistols.
avatar Re: Euclase
August 02, 2012 12:39PM
    
Owen,

The crystal you show is undoubtedly euclase. While the cross section appears to be hexagonal, the termination, striations and zoning are readily distinguishable and your SG reading backs that up. The orginal post in question has no termination, there are no striations that can be seen in the photos and no obvious colour zoning. Based on the photo and without more information, to me it still looks like beryl. It could still turn out to be euclase if more tests are done to determine, as I suggested an SG test would probably settle the matter.

regards,
stephanie smiling smiley
avatar Re: Euclase
August 02, 2012 03:56PM
Thanks Rock and Stephanie for the helpful comments. What prompted me to post was I recently lost a small bet as a result of a monoclinc xtl aping an a=b=c octahedron - and here it is aping (at first glance) a hexagonal prism (in my specimen). I agree with you too, Stephanie, that Gabriel should test it's SG; he's got a good size and fairly clean chunk so that could squeeze out Euclase. Beryl would be my likely guess too..

Given its size, it's probable that a couple of clean gems of good weight could be cut out of it. Even at Goshenite prices, Gabriel should find a lapidiarist willing to pay more that USD 20 for a partly gemmy piece more than 300cts overall. Say USD 50? Maybe more if being bought not for stock but with a definite project in view. Better pictures help buyers to open up. No one wants to buy a blur.
Re: Euclase
August 04, 2012 01:18AM
Owen, I have 2 euclase crystals with hexagonal habit--both from near Ouro Preto. Both have a deep blue color and came with a lot that had xls with a more common habit. I think the hexgonal xls might be pseudomorphs.
avatar Re: Euclase
August 04, 2012 04:10PM
Hi Ray,

I wonder (truly, I'm still learning the ins and out of the range of crystal habits and expect to continue doing so for quite some time). Take a look at this, a cross-sectional view of an elongated Baddeleyite.


This is a fairly typical cross section for a monoclinic piece. There are six sides, one pair of sides of this six-sided prism are much longer than the others. Now, imagine this crystal to be in a standard three-dimensional xyz liniear graphing matrix. Rotate the view in your mind, so the longest axis in the cross-section is parallel to the y axis. Maintaining that same viewpiont, then rotate the xtl about the x axis. As one does that, then on the y axis scale, to which the long pair of prism sides have been made parallel, this pair of sides will seem to shorten and lengthen, between some maximum and minimum dimension. At one point between maximum and minimum positions, the longest pair of sides will look equal in length (from this viewpoint) to the other four sides making up the cross-section. Et voilĂ , from this view of the xtl, one then sees a regular hexagonal cross-section, albeit because the xtl is so well rotated about the x axis that c axis of the xtl is well out oif true with the z axis of the matrix (i.e. well off 90 deg intersection with the x and y axes smiling smiley So whilst one can view a regular/near regular hexagonal cross-section. the xtl is not of the hexgagonal system but is typically monoclinic.

So far so good. But what remains a wondering for me is how, in a monoclinic xtl, this regular hexagonal cross-section can be approached when the xtl's c axis is at or very close to 90 deg intersection with the a1/2/3/ axes as it seems to with some Euclase? Is this a characteristic of polymorphism or is it something else?



Edited 1 time(s). Last edit at 08/05/2012 01:30PM by Owen Lewis (2).
avatar Re: Euclase
August 05, 2012 04:38PM
    
Accidental growth features can mask the true synmmetry, increasing or decreasing it. Elongated fluorite or galena cubes appear as orthorhombic prisms and Zekserite was thought hexagonal pink apatite until Jack sent it to Pete Dunn. If one has more than one xl and looks carefully the symmetry can usually be sorted out.
Re: Euclase
August 05, 2012 09:23PM
Hi Owen,
I've seen similar accidental habits like this. I have a few garnet crystals that look hexagonal. However, the euclase xls are so clearly a hexagonal habit that I think, given the chemical similarity, it has to be a pseudomorph.
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