coldwater
off to a rocking start
Member since June 2024
Posts: 1
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Post by coldwater on Jun 30, 2024 13:30:36 GMT -5
Hey everyone, I’m glad to join this forum and converse with all you wonderful people. This is my second year of rock hounding. I was searching the beaches of Lake Huron and I found a bunch of rocks that look like this. ![](https://res.cloudinary.com/df4pwobj7/image/upload/v1719770040/vysrzmrjx5xoseaf6ee3.jpg) (This one is a little over 2 pounds) I think they are cold water agates but I’m not sure. Any insight into what they are would be welcome. Their primary attribute is a transparent crystalline structure with blue with yellow colours with some having botryoidal features. I would love to see pictures of your cold water agates to compare with. I’m thinking of joining a local lapidary club so I can cut open some of these open and see if there is any banding. Any tips of tricks on cutting these rocks would be much appreciated. Keep in mind I’m a total beginner. Here is a picture of them all together: ![](https://res.cloudinary.com/df4pwobj7/image/upload/v1719770952/vdgq0gsxfnobqj3nxjtn.jpg) I hope all have a great weekend. Stay frosty. - coldwater
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Post by vegasjames on Jun 30, 2024 18:29:25 GMT -5
Welcome from Southern Nevada.
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titaniumkid
spending too much on rocks
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Post by titaniumkid on Jun 30, 2024 19:42:05 GMT -5
Hi from Australia ![:)](//storage.proboards.com/forum/images/smiley/smiley.png)
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chris1956
fully equipped rock polisher
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Post by chris1956 on Jun 30, 2024 20:49:10 GMT -5
Welcome from Missouri. Someone here knows about cold water agates but can't remember who.
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Post by liveoak on Jul 1, 2024 8:57:39 GMT -5
Welcome from NW Florida
Patty
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Post by jasoninsd on Jul 1, 2024 22:24:43 GMT -5
Welcome to the forum from South Dakota! ![:)](//storage.proboards.com/forum/images/smiley/smiley.png) I don't have any experience with Coldwater Agates...but they look gorgeous!
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Post by cabby on Jul 1, 2024 23:35:19 GMT -5
Welcome from Wisconsin! No cold waters in my neck of the woods, so can’t help with that! But my favorite YouTube (rock related) channel is planetarylapidary, which finds and collects a heck of a lot of them! Also various cherts and stromatorporoids, which some might be… hopefully that can help while waiting for the forum experts.
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rocknrob
Cave Dweller
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Member since May 2024
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Post by rocknrob on Jul 2, 2024 23:08:57 GMT -5
Hi there from Washington State! I've never heard of cold water agates although if the temperature of the water is a qualification I would say most of the PNW is cold water ![;)](//storage.proboards.com/forum/images/smiley/wink.png)
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ThomasT
has rocks in the head
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Post by ThomasT on Jul 3, 2024 16:13:02 GMT -5
Coldwater, Howdy from Tennessee.
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gemfeller
Cave Dweller
Member since June 2011
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Post by gemfeller on Jul 3, 2024 20:05:41 GMT -5
I'd never heard of coldwater agates. Did a lot of looking and I'm still not clear on what they are except they seem to be a type of Laker agate that forms in the crevices in chert. Seems to be a Great Lakes or Lake Superior thing. Anyone have a complete description?
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Post by cabby on Jul 3, 2024 20:17:17 GMT -5
I'd never heard of coldwater agates. Did a lot of looking and I'm still not clear on what they are except they seem to be a type of Laker agate that forms in the crevices in chert. Seems to be a Great Lakes or Lake Superior thing. Anyone have a complete description? They are agates found primarily in Michigan. The area overlaps with lakers but they form in different conditions and are normally very pale blue, white, and/or colorless (more pure of silicates). That’s as much as I know, since I’ve never lived in the area. A lot of people consider them to also be lakers… I won’t start ranting again 😆
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Post by Starguy on Jul 4, 2024 11:29:09 GMT -5
I’ve never heard of cold water agate. Could it be called that because the silica was deposited by cold (surface) water infiltration instead of from hot sub-surface replacement or filling of vugs?
Welcome from Idaho.
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gemfeller
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Post by gemfeller on Jul 4, 2024 13:08:49 GMT -5
I’ve never heard of cold water agate. Could it be called that because the silica was deposited by cold (surface) water infiltration instead of from hot sub-surface replacement or filling of vugs? Welcome from Idaho. Starguy Here are several definitions I've found in (inomplete) searches. Apparently it's a name to describe agates that form in sedimentary rocks instead of volcanics i.e., vesicular agates. At least that's what I take from it. Volcanic agates are presumably formed from a hot water feedstock while thse agates derive from cold water. www.michiganrockhounds.com/articles/agatesCold water agates are a different breed. These form in limestone and they have a special name because they are thought to form in a special way (we’ll talk about that in a moment). These form in limestone and are almost always completely colorless, composed of clear and milky white bands. They’re found abundantly in Southern Michigan where limestone is common and they’re often quite small. While lacking the bold colors of their northern cousins, they can still be remarkably beautiful. *********** And so this is the way we have known that agates form for years and years now. Agates only form in the vesicles of volcanic rocks by the process described above, end of story… except for those dang cold water agates that seem to be fairly unique to Michigan. These are colorless agates that are found in limestone. So… after finally acknowledging that they do in fact exist, a new model was proposed for these weirdo agates: they must have formed in cracks and cavities- hollow spaces- in the limestone and dolostone rocks and formed in pretty much the exact same way as the volcanic rock agates. ********** A cold water agate is a type of agate that is marine sedimentary and mostly formed in Devonian age limestone, which is 416 to 358 million years old. It is significantly different from the 1.1 billion year old Lake Superior agate that formed in igneous basaltic rock.
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Post by Starguy on Jul 4, 2024 16:32:11 GMT -5
Great article Rick gemfeller. Agates have always fascinated me. I’ve met my share of geologists with the “why bother” attitude about them. On the other hand, they’re usually pretty interested when you hand them a nice one. It seems funny since they are such durable rocks. No mineral is an ore unless it has commercial value. I’ve certainly payed for plenty of agates. They are great in crushed aggregate. Thanks for posting the link.
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pebblesky
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Post by pebblesky on Jul 4, 2024 17:06:50 GMT -5
Did a google search and came across this wiki: encyclopedia-gemstonia.fandom.com/wiki/Coldwater_agateThere seem to be some botryoidal textures on some of the specimens you have shown. I guess some of them will reveal bands, tubes and orbs depending on which direction you cut them.
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gemfeller
Cave Dweller
Member since June 2011
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Post by gemfeller on Jul 4, 2024 18:11:35 GMT -5
Did a google search and came across this wiki: encyclopedia-gemstonia.fandom.com/wiki/Coldwater_agateThere seem to be some botryoidal textures on some of the specimens you have shown. I guess some of them will reveal bands, tubes and orbs depending on which direction you cut them. Well, if the name info in the link you posted about it being named for Coldwater Quarry where it was first found is right, it shoots my theory of cold water vs. hot thermal water into blithereens. More research is indicated when I have time.
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Post by Son Of Beach on Jul 4, 2024 19:56:33 GMT -5
Here is what I would think you would call cold water agatization? I found this in Wilderness State Park at the tip of the lower peninsula of Michigan. It looks like a chert material with fossils and there are agate inside the fossils. I sometimes find small amounts of banding in quartz veins within chert that I find here in Missouri also. ![](https://res.cloudinary.com/rth-new-member/image/upload/v1720135553/new-members/wk7xjbyxwlfpaopczxsl.jpg) ![](https://res.cloudinary.com/rth-new-member/image/upload/v1720135553/new-members/x2vwxiyj3aly1cdy4txt.jpg) I've seen some things like that Chris, but nothing as well defined.
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