white rocks

[Bajahunter]

I have found some white translucent rocks. Some look like lace agate, but this rock is too soft. It is between 4 and 5.5 hardness. It can be scratched by a soft steel nail, but not by a penny.
The first pics show a couple of raw pieces from different angles. You can see the layering on the right side piece. The left side shows how some of it got folded up. The outside layer on the right piece is microcrystaline The inner layers are more amorphous/no crystals.
The last 4 pics show some 1/8 inch slabs on a light box and then in normal light. Some are more polished than others. When polished it takes on a greasy feel. The smaller circle is the size of a nickel. Some larger pieces cast a honey yellow hue when held to the light.
I think it might be Opal C/CT. There are beds of diatomaceous earth in several locations nearby.
I am interested in any opinions.
Rob

 

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[Bajahunter]

Wiz
No hopes to dash.
Common Opal or Opal C is ....common.
Not a gem quality opal at all.
It is the closest thing I can find with an internet search.
The main thing is that it is too soft for agate/calcedony and too hard for soap stone.
This was obviously put down in layers and some of it got folded later on.
It is in an area of of volcanic activity. possibly a part of a proto Sea of Cortez
What's fun is to see the different patterns that are in the rock.
It's value is to be found in what I can do with it.
Thanks for your input.

 

[Bajahunter]

Here are some shots of the biggest piece.
It is sitting on my light box. The area that is translucent in first pic is 2.5 x .5 inches, the second is 3.75 x .5 inches.
I have shaped it up some on a grinder but no polish yet.
The side that is sitting on the light box is the last picture, also with a little grinding. It just looks like an opaque whitish surface.
Again you can see the layers of translucent material, and the darker sediment that covered it up on top

 

[Eu_citzen]

Could it be related to calcite? Reacts with weak acids.

 

[Bajahunter]

Haven't tested with acid yet.
It is too hard for calcite. Also no crystals, or in some cases of microscopic size. Need a loupe to see.

 

[Eu_citzen]

Try with acid. It seems to be of sedimentary origin.

Don't have a great deal of experience with that.