<p>I believe it’s a portion on an <a href="https://en.m.wikipedia.org/wiki/Amethyst" rel="nofollow noreferrer">amethyst geode.</a></p>

<p><a href="https://en.m.wikipedia.org/wiki/Amethyst" rel="nofollow noreferrer">amethyst geode</a></p>

CC BY-SA 3.0
2017-12-03T11:13:50.630Z
From a scratch test I agree that it should be relatively hard. Also, lack of cleavage planes and the growth lines suggest it's amethyst and not fluorite. I cannot think of any other similar mineral harder than amethyst (even including very expensive ones).
Gabija
CC BY-SA 3.0
2017-12-03T23:47:38.300Z
I agree **amethyst**. Geode fragment from the lines and banding. I'd assume that 4th picture has glow from UV light reflecting off surface, not fluorescence of the rock itself. Also when scratched on corundum (Mohs hardness 9) quartz (Mohs hardness 7) would leave white line of quartz powder. So is the scratch really *in* the corundum or is there just white dust trail on the corundum? Diamond (Mohs hardness 10) is about the only thing that would really scratch corundum.
MaxW
CC BY-SA 3.0
2017-11-30T23:38:03.137Z
2017-12-01T00:00:53.897Z
2017-12-01T00:00:53.897Z
Jeffrey Boettger
<p><img src="https://i.sstatic.net/mEpfz.jpg" alt="enter image description here"><img src="https://i.sstatic.net/pOZ9f.jpg" alt="enter image description here"><img src="https://i.sstatic.net/c2Q82.jpg" alt="enter image description here"><img src="https://i.sstatic.net/8hRUS.jpg" alt="enter image description here"><img src="https://i.sstatic.net/DS5KR.jpg" alt="enter image description here"></p>

<p>I don’t know much about gems so I tried to upload pictures in different lighting.</p>

<p>The corundum pic
Pictured with it was scratched by this stone.</p>

<p>I can’t tell if the corundum scratches this stone.  It doesn’t look like it to me.</p>

<p>It was found in the Deposit Dan active volcano.</p>

CC BY-SA 3.0
2017-12-01T11:13:49.943Z
That should read, an active volcano.  That photo was taken under a black uv light long wave.
user11321
<geology>
What stone is this?
user11321
# What stone is this?

(Asked by: username_0 on 2017-11-30)

![enter image description here](https://i.sstatic.net/mEpfz.jpg)![enter image description here](https://i.sstatic.net/pOZ9f.jpg)![enter image description here](https://i.sstatic.net/c2Q82.jpg)![enter image description here](https://i.sstatic.net/8hRUS.jpg)![enter image description here](https://i.sstatic.net/DS5KR.jpg)

I don’t know much about gems so I tried to upload pictures in different lighting.

The corundum pic
Pictured with it was scratched by this stone.

I can’t tell if the corundum scratches this stone. It doesn’t look like it to me.

It was found in the Deposit Dan active volcano.

**Tags:** geology

> **Comments:**
> **username_0**: That should read, an active volcano.  That photo was taken under a black uv light long wave.  

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## 1 answers

### Answer by username_1 on 2017-11-30. Score: 3

I believe it’s a portion on an [amethyst geode.](https://en.m.wikipedia.org/wiki/Amethyst)

[amethyst geode](https://en.m.wikipedia.org/wiki/Amethyst)

> **Comments:**
> **username_2**: From a scratch test I agree that it should be relatively hard. Also, lack of cleavage planes and the growth lines suggest it's amethyst and not fluorite. I cannot think of any other similar mineral harder than amethyst (even including very expensive ones).  
> **username_3**: I agree **amethyst**. Geode fragment from the lines and banding. I'd assume that 4th picture has glow from UV light reflecting off surface, not fluorescence of the rock itself. Also when scratched on corundum (Mohs hardness 9) quartz (Mohs hardness 7) would leave white line of quartz powder. So is the scratch really *in* the corundum or is there just white dust trail on the corundum? Diamond (Mohs hardness 10) is about the only thing that would really scratch corundum.  

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