Rio cobbles

Share and share alike mohs. RTH is made interesting by a wide range of personalities with similar earth and social interests.
RTH has been a fine haven for many folks. Glad that it has served your needs well. We all must be in the same boat.

The caliche was a new experience for me. Talk about reflecting light and cooking your armpits ! I spent a lot of time sampling the agate density in caliche at various locations. The agates jaspers and petrified jewels were locked into the caliche within a half mile of that Rio Grande river channel. Much of it requires a hammer and screwdriver to chisel and pry agates out of it. The gravel yards would scrub the glue-like caliche off of the gravel if they wanted it clean. No surprise your Native folks used it for construction.

Looks like I am planning another safari out to the Rio. I am sawing these Rio's for the fun of it but also to re-familiarize myself with reading the skin of each cobble. The patina lends to deception as to what beauties lie within. There is mega quantities of agates at the cool lakeshore but they have all been painted with a white (alkaline ?) coating. Well camouflaged from the eye of the collector, hidden treasured covered with earth paint !

Cobbles with these formations almost always guarantee fine plumes and mosses(include a conglomerate and a striper):



This one shows the point of infill, a homemade glass agate

Looks like New Mexico wonderstone rhyolite. Always well silicified rhyolites that polish well. stolen from upstream thank you



Looks Woodward and an old chip off of a big cobble. Travel 400 miles to Big Bend Rio and see park agates as big as basketballs.




Dark moss



Closer, note gold like inclusions(old iPad pro does OK)



Bicolor moss



a world within



Another dark with longer plumes, milkier chalcedony

A favorite of mine porcelain jasper. Probably washed out from Chihuahua province of Mexico. Fairly common at L Falcon.



A small bicolor



Not so pretty but interesting

Yes the porcelain is so varied and good hard shiny material. It is mined in or close to a silver mine.
There are still some loose ends doing the trip. Mainly connecting with land owners.

Ooh, cut that green and gold plume the other way. Yall chopped across the plume ends. Should show great plume cut parallel to the tips.

It is a massive deposit of so many varieties Jason. The Rio drainage covers a large area known for these quartz rocks. They all washed down and covered the flat lands of south Texas. The deposit runs for at least 100 miles. I'm collecting on just a few of those miles ! You never know what will be found from minute to minute.

Wood or root judging from the knots. Looks like lots of alteration thru silicification has occurred. In many cases the surface of the cobble will display wood patterns but after cutting you have to wonder if it is a plant at all. As if the wood served as a carrier for color and distorted patterns. Exposed patches of limestone or caliche covering 1/4 to 1 acre often have a petrified collection of a similar wood pattern as if in situ.



Nice moss bi-color. probably better cut rotated 90 degrees to show plumes better



Some of the conglomerates are bright and amazing. This on on the dark side.



From past trip with white matrix:



Banding

I couldn't find the conglomerate photo album.
The Texas Gem Trail book does specify the CJ Young ranch on the Brazos River just west of Dallas as a large source of conglomerates.
Since the Brazos flows directly into the Gulf of Mexico the Rio conglomerates are coming from a different source.
One of the conglomerates had equally spaced BB sized agate chips frozen in crystal clear chalcedony.
The ones with the white/beige matrix were similar and highly sought after but unfortunately infrequent.

Not the best Robin:



this matrix color was most common:

Surprised a low grade poppy. Will have to pay attention to poppy agates next time !



closer in on so-so poppy orbicular:



A mystery with specks of copper ?