Wyoming Iris agate

Wyoming Iris agate is found along the Wind River. It is know as Wind River iris agate. Most of the pieces found are petrified wood limb casts that have been wholly replaced by chalcedony in a water line agate form. Some of the layers are moss agate others are opaque to semi opaque while others are nearly water clear. Some of the limb casts have botryoidal agate or quartz crystals on the inside. Finding the iridescence is a bit of a challenge but a skilled lapidary craftsman will have luck with persistence. 


Wind River iris agate rough. Straight from the agate collecting area unwashed or prepared. This is what it would look like if you went rock hunting looking for it.

Some of the iris agate still has a bit of recognizable form of the wood it has replaced. Only the outside of the agate casts show the petrified wood structure. The inside has been completely replaced destroying any internal structure.

The outside petrified wood casts often show bore holes and areas where the wood was rotting before it was petrified.


Water line agate structure fill the inside of the iris agate limb casts. 

The layers of the iris agate have varying degrees of translucency.

The outside layer of the iris agate limb cast is 1/8 to 1/2 inch thick and is the only part that retains the petrified wood structure.

In rare cases the inside of the casts form alternatating bands of quartz crystals and fortification agate.

Sometimes the centers of the iris agate form botryoidal agate or quartz druzy.

In super rare cases the center cavity never filled all the way producing the most sought after specimen pieces.

The iris agate likes to cleave along the layers. Out in the agate collecting beds you will find thin perfectly flat pieces where this has happened. These natural agate slabs are ready for cabbing right off the ground. I could also see this material being used as cameo agate rough. If you have ever cut a cameo from this material let me know. I'd love to see it.

Trip reports from the collecting areas

collecting site maps coming soon.











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