Joined: Sun Aug 15, 2010 11:39 pm Posts: 21 Location: Colombia
I found two crystals in a parcel with very rare inclusions. They look as though they have been faceted using the micro concave method.
I wanted to share them with you as I have never seen anything like this during my years working with emeralds. I have asked many dealers and they have never seen inclusions like this before. A true collectors piece.
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Post subject: Re: Unique Colombian emerald inclusions
Posted: Mon Sep 27, 2010 3:26 am
Gold Member
Joined: Fri Oct 19, 2007 5:04 pm Posts: 1642 Location: Walnut Creek, CA
What freaks me out is that a similar (at first sight...) and peculiar feature is occurring in two different minerals with very different symmetry... Any feature at the top (pinacoid) of the crystals? Like a double spiral made of little steps? Something similar to this (look at the picture on the right, it's more clear):
Post subject: Re: Unique Colombian emerald inclusions
Posted: Mon Sep 27, 2010 3:42 am
Gemology Online Veteran
Joined: Sat May 22, 2010 2:51 am Posts: 755 Location: South Africa
These helical inclusions also occur in aquamarine. Some time ago John White posted a picture of one in a cut stone on Jorde Fabre's FMF forum, and then I found one in my collection of rough. As far as I know, no-one has come up with an explanation of these helical growth features. My example does not have a core of foreign material. I analysed the cut-off end using EDS in a SEM and it showed nothing but beryl. The growth feature consists of a helical crack, with an even pitch, and regularly spaced wing-liked, paddle-shaped 'extensions'. it is really interesting to see the example in topaz.
Duncan
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Helical feature in aquamarine.jpg [ 64.87 KiB | Viewed 6694 times ]
Post subject: Re: Unique Colombian emerald inclusions
Posted: Mon Sep 27, 2010 4:29 am
Gold Member
Joined: Fri Oct 19, 2007 5:04 pm Posts: 1642 Location: Walnut Creek, CA
In my opinion the process it's probably driven by the xtl growth mechanism, in this case EDS wouldn't give many answers. The SEM images you took were on the "natural" top of the xtl or it was a polished surface? Any "hole" with a peculiar shape and/or steps close to the axis of the feature?
Post subject: Re: Unique Colombian emerald inclusions
Posted: Mon Sep 27, 2010 11:56 am
Moderator
Joined: Fri Jun 25, 2010 10:06 pm Posts: 2267 Location: Chapel Hill, NC / Toronto, ON
That is by far the single coolest emerald I've ever seen. PLEASE DON'T CUT IT!!! A perfect specimen showpiece if I ever saw one.
You know...polishing the edges into a hex shape and putting it on a necklace doesn't sound bad either...but that would be ruining its naturalness. Then again...
Post subject: Re: Unique Colombian emerald inclusions
Posted: Mon Sep 27, 2010 10:06 pm
Established Member
Joined: Sun Aug 15, 2010 11:39 pm Posts: 21 Location: Colombia
I am amazed to learn that the same inclusions occurs in topaz and aquamarine. Thanks for the photos they are great.
I am not going to cut any of this stones but they could be worn as they are as pendants. None of the sides of the stones have been polished to my knowledge.
Post subject: Re: Unique Colombian emerald inclusions
Posted: Tue Sep 28, 2010 8:05 am
Moderator: Lapidary Arts and Tools
Joined: Tue Jun 12, 2007 6:41 pm Posts: 5534 Location: Massachusetts, USA
If all these mineral crystals are hydrothermal, and the gas pressures are at equilbrium, maybe a bubble was excluded from the crytallizing lattice, resided for a while, then again excluded, rose, sat there, etc.
Just a wild desperate guess. If the liquid is saturated with gas, there is no reason for the bubble to be dissolved, or have anywhere else to go.
Post subject: Re: Unique Colombian emerald inclusions
Posted: Tue Sep 28, 2010 9:18 am
Moderator: Lapidary Arts and Tools
Joined: Tue Jun 12, 2007 6:41 pm Posts: 5534 Location: Massachusetts, USA
Quote:
I though perhaps it was water rushing through the crystal as it was forming, hence the swirling type of inclusion left.
Looks like ithe bubble was stopping, sitting, and starting. Note that in the spodumene, the zigzag effect may coincide with cleavage planes. The crystal tried to grow perfectly but is disrupted by the inclusion.
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