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 Post subject: Waterworn Cumberland-habit Amethyst
PostPosted: Wed Oct 05, 2016 7:02 pm 
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I ended up buying this from an ebay seller that was auctioning off a fair bit of african rough, is a bit worn but the hexagonal bipyramid shape is pretty obvious. It's a pity the larger tip has a stress fracture that will reduce recovery when I cut it.

Would it be worthwhile to have a thread for showing unusual amethysts people have found over the years?


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File comment: Under water in sunlight to show phantoms.
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 Post subject: Re: Waterworn Cumberland-habit Amethyst
PostPosted: Thu Oct 06, 2016 10:38 pm 
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Nice colour to that one. I have seen some interesting and unusual amethyst sceptres come from Lowmead. Lowmead seems to produce the bizzare shapes.


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 Post subject: Re: Waterworn Cumberland-habit Amethyst
PostPosted: Fri Oct 07, 2016 12:22 am 
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Lowmead's amethyst has always held my interest due to the taller amethyst crystals that you get there, though it will be a while before I go fossicking there due to wanting to avoid areas with the short double terminated crystals...
Oberon looks like it isn't too far away though, I might try there out next year if I have time for it. What little I have seen of the amethyst there matches with the Nigerian material I bought a while back.
I've also found your pictures in the Mining Corner and in the Lowmead thread on Prospecting Australia to be helpful in figuring out what happened to the crystals there while they were forming.
It's a real pity that the area seems to have suffered from some sort of ground movement after the amethyst formed, to give so many perfect but heavily cracked crystals.


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 Post subject: Re: Waterworn Cumberland-habit Amethyst
PostPosted: Fri Oct 07, 2016 2:01 am 
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Yeah, it is a real shame. Ktmman's friend from England found the biggest one I've seen there, about four to five inches long, deep purple and almost totally crack -free. Beautiful crystal.

Do you think proximity to the surface in a soft, loose soil might be part of the reason so many are cracked? Shallow crystals might have been exposed to the intense heat of bushfires an 12 000 years ago there was an ice age so the ground would have probably frozen and thawed each year, expansion and contraction.

Here's an observation from five years of digging in the area. The crystals are in a soft decomposed granite sand, resting on a hard floor of decomposing but still solid granite (but it can be broken with a crowbar). They are often perfectly formed but only the occasional one is not cracked. But now and then you strike a pocket or pipe of crystals that extends down into the hard floor. The crystals retrieved from these are often almost crack-free, about the best you will find there. If there are inclususions in these ones they are usually bubble veils rather than cracks.

I can't really think of any reason that they are not cracked other than that their greater depth and being still embedded in a small space within a hard, unmoving medium has protected them from some of the stresses that the shallow ones in the soft medium have been (and continue to be) exposed to.

What do you think?


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 Post subject: Re: Waterworn Cumberland-habit Amethyst
PostPosted: Fri Oct 07, 2016 4:02 am 
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I wouldn't know much about what occurred around Lowmead during an ice age but I think you are spot on about the granite protecting them from ground movements.
Everything in that granite sand layer and above is going to be slowly rolled around by soil movement and any floodwater that drains into the layer is going to lift it up and drop it on itself as it runs through. Imagine grinding boiled sweets against two steel plates.

Bushfire effects could explain those weird orange citrines people seem to find, if anyone ever finds a flawless one that isn't the true smokey-style citrine I'll be surprised. It's just the wrong shape and colour to have formed that way...


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 Post subject: Re: Waterworn Cumberland-habit Amethyst
PostPosted: Thu Nov 17, 2016 12:55 am 
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I sure do love me some unique. odd, or interesting amethyst.
I don't discriminate against any color, especially purple!

Not easily seen in this photo, but here is a deep, super saturated amethyst with the cumberland habit. They look smoky but are actually purple. Reminds me of some old school Pennsylvania amethyst or that dark India material
Dug bunches in Virginia


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 Post subject: Re: Waterworn Cumberland-habit Amethyst
PostPosted: Thu Nov 17, 2016 9:25 pm 
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Very nice Jason, while I don't doubt those have some smokey-coloured phantoms in them, I assume the orange is the reflection of the warm light off the veils in the roots of the crystal.
Would probably look amazing in the mid-day sun given how dark they are in that lighting.


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 Post subject: Re: Waterworn Cumberland-habit Amethyst
PostPosted: Thu Nov 17, 2016 10:19 pm 
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Nice specimen!


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 Post subject: Re: Waterworn Cumberland-habit Amethyst
PostPosted: Sat Dec 03, 2016 3:32 am 
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Yea, the color was something to be desired. We hit great stuff when we dug but much of it was super saturated and blacked out or the purple color was spotty in the smaller points with the orangish/brown roots hampering the quality.

Now that I think about it, you are right, and I was mistaken about the cumberland material. The cumberland crystals we got were all dark, smoky in color or black. I apologize for my lapse of memory. We gots lots of cumberland crystals and clusters and at first we thought they were beta since they were so opaque and dark and the vein was formed very deep at a high temp.. Lots of that "burnt" look with the veins. After checking out John White's lit. on distinguishing beta from normal, we knew they were not beta points. Some of the singles looked like a spot on match when compared to the Italian stuff.
A strange deposit for sure. Probably one of the largest finds of cumberland type quartz ever found in the eastern part of America. I was not a full share recipient, since I didn't fork out $2000 in the split for the trackhoe, but I still got a good amount of cumberland's for my 15% or so final take.

Here are some of the amethyst we were finding....color was awesome in some, but they were small and very touch and go in color and quality
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Here is what it typically looked like...smaller crystals had better color....bigger were to saturated


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 Post subject: Re: Waterworn Cumberland-habit Amethyst
PostPosted: Sat Dec 03, 2016 4:33 am 
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I like that blue-tinted colour, I've not found that in this area. The ones at this site can often have a smoky tint but change markedly over a short distance. This one is fairly typical of the colour..

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