<p>Agate sometimes contains fossils. Your specimen seems to contain a fossil crinoid disc, and probably there are more than one. Crinoids are plant-like animals anchored to the sea bed, and are sometimes called sea lilies. Many species  became extinct millions of years ago, but a few survive today. The stems of ancient crinoids were made up of stacked discs, rather like the one in your agate. When the crinoids died, their stems often disintegrated, and the discs became scattered. The hole you mention is the hole found at the centre of all crinoid discs. For some reason it did not become full of agate, perhaps because there was a gas bubble or some other obstruction in there. I can't predict what you would find if you cut it in half, that decision is entirely up to you. I think it would probably be best to leave it as it is.</p>

CC BY-SA 4.0
2019-09-03T17:45:06.650Z
I didn't regard this as a rock ID question, as the rock was already identified. It was about the cause of the hole and the pale ring around it.
Michael Walsby
CC BY-SA 4.0
2019-09-04T00:08:41.673Z
Thank you so much! I had no idea! I found this in a place not typical of Lake Superior type agates and feel lucky to have seen it on a hillside under a leaf!
Kara Mc
CC BY-SA 4.0
2019-09-04T00:10:09.660Z
Thanks! I am a beginning rock hounder. Thanks for letting me know! Really appreciate the great info!
Kara Mc
CC BY-SA 4.0
2019-09-04T03:41:17.673Z
Well not exactly. I am guessing it MAY be a Lake Superior Agate? Not 100% on that. You are right, it is more of a question on rock features and lapidary. Changed my ID to geology...Rock on!
Kara Mc
CC BY-SA 4.0
2019-09-04T06:41:49.037Z
Agate is good enough.
Michael Walsby
CC BY-SA 4.0
2019-09-02T23:09:20.457Z
2019-09-02T23:09:20.457Z
Michael Walsby
<p><img src="https://i.sstatic.net/yXHNS.jpg" alt="enter image description here"></p>

<p>I found this rock in Western Wisconsin. Pretty sure it's a Lake Superior Agate?</p>

<p>Wondering what would make the white eye that has red in its center?</p>

<p>Would this rock be a good one to have someone cut in 1/2?</p>

<geology>
What Makes Round Holes In Superior Agates?
Kara Mc
# What Makes Round Holes In Superior Agates?

(Asked by: username_0 on 2019-09-02)

![enter image description here](https://i.sstatic.net/yXHNS.jpg)

I found this rock in Western Wisconsin. Pretty sure it's a Lake Superior Agate?

Wondering what would make the white eye that has red in its center?

Would this rock be a good one to have someone cut in 1/2?

**Tags:** geology


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## 1 answers

### Answer by username_1 on 2019-09-02. Score: 2

Agate sometimes contains fossils. Your specimen seems to contain a fossil crinoid disc, and probably there are more than one. Crinoids are plant-like animals anchored to the sea bed, and are sometimes called sea lilies. Many species became extinct millions of years ago, but a few survive today. The stems of ancient crinoids were made up of stacked discs, rather like the one in your agate. When the crinoids died, their stems often disintegrated, and the discs became scattered. The hole you mention is the hole found at the centre of all crinoid discs. For some reason it did not become full of agate, perhaps because there was a gas bubble or some other obstruction in there. I can't predict what you would find if you cut it in half, that decision is entirely up to you. I think it would probably be best to leave it as it is.

> **Comments:**
> **username_1**: I didn't regard this as a rock ID question, as the rock was already identified. It was about the cause of the hole and the pale ring around it.  
> **username_0**: Thank you so much! I had no idea! I found this in a place not typical of Lake Superior type agates and feel lucky to have seen it on a hillside under a leaf!  
> **username_0**: Thanks! I am a beginning rock hounder. Thanks for letting me know! Really appreciate the great info!  
> **username_0**: Well not exactly. I am guessing it MAY be a Lake Superior Agate? Not 100% on that. You are right, it is more of a question on rock features and lapidary. Changed my ID to geology...Rock on!  
> **username_1**: Agate is good enough.  

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