I have seen the same material from Idaho before. I have collected it personally in California though, it is from the Northern Cady Mountains, North and East of Barstow California. It occurs near the Sagenite Agate area in the North Cady's that Mary Francis Strong wrote about in her Collecting guides. I have some of it in a bucket on the side of the house but would have to dig for it at this point. Pat McMahon might have a sample of the same North Cady Plume on his site for reference. I will look quickly on Pats site and see if I can grab a link to it.
I checked his site and he only has 5 Cady Mountains images now, his site changed since he brought out his book on Agates with Inclusions. One of the 5 images is from Baxter Wash (Which is North Cady's) and is the material I mentioned it just doesn't have the intense green that is also found in the plume from that area. His picture (also the only picture of it in his book - just checked) just has some faint Green in the center of the plume so it is not a great side by side comparison to the one you show.
Next time I go digging in buckets I will look for the sample but I can attest to the piece you have being identical to the material I have collected there.
