FMF - Friends of Minerals Forum, discussion and message board

[Ashley Ratcliff]

I found about 20 of these in one very specific spot off castle hot springs road. I've putzed around in the desert for years only found these in this spot. Any body have any experience with these? Please help identify what they are? How common are they? Again they are just littered off the highway in this one spot but havent found them anywhere else.
Thank you for the help.
Ashley

[Pete Richards]

Nice photograph! Is the object about 1/4"?

In order to help you further we need some information that you can provide. Will one of these objects fizz in warm vinegar? Will an edge of one scratch a knife, or will a knife scratch it?

Were these by, near, or part of a piece of rock or a ledge of bedrock? Can you find out anything about the local geology?

[Ashley Ratcliff]

It's about 1/4 inch. (Its the smallest one yet most defined). It scratches the knife. However some parts are more fragile than other parts. It does not react to warm vinegar. They are loose on ground. Some of them have some quartz composition. In the same area I found abundant druzy geodes, and some of the best quality large chalcedony rosettes I've ever seen. The collection site was close to lake pleasant regional park which currently is a reservoir. Historically had active volcanic activity. Indian ruin, and was covered by ancient oceans long long ago (here say). It was found in the dirt. No obvious bedrock at site just dirt but was about a football field away from a rock cliff, they were found about midway up the mountain.

[Ashley Ratcliff]

I forgot some geography:

Not sure if it matters but temp ranges from about 20 F to 120F. It is desert about 10 mi from the base of the Bradshaw mountains that jump from desert to forest rapidly.

[Volkmar Stingl]

These should be ironstone concretions in sedimentary rock.

[Ashley Ratcliff]

Thank you

[Poorboy]

Search for "agate skin" on the internet and scroll through the images. Your mention of chalcedony and geodes were the key clues for the association. Your pieces probably eroded from a vesicular andesite (intermediate extrusive igneous rock), somewhere in the pile of volcanic rocks in the vicinity of where you found these, as the skins weather relatively quickly.

[Poorboy]

Also try "agate husk" for comparable images; this worked better with Google