Texas Banded Chert

Nice ones!  Can't wait for the final polished pics.  

Those already look amazing!

They look awesome!

We’ve found a lot of banded chert but only a few have really caught my eye. This one I found walking my dog down the creek wash recently. It’ll go by the front door for a while until I think of what to do with it. May just clean it up in the rebel 17 with a lot of smaller stuff for a couple weeks. More often than not, polishing these rocks fully ends up with slightly swirly, rather plain chunk of chert. Usually I partially tumble them until the character comes out, then stop and polish in the vibe. This one’s big though, so won’t work in my vibes. It’ll make a nice yard rock at least.

 They polish beautifully, often similar to the first one I posted. Just have to know when to stop the course stage… or even which stage to start at. Sometimes I just do them in my vibratory with 280 sic to clean them up. I’ll post pictures later. I have to round up the good ones after I get the kid to school.

Thanks! Here’s a few that I stopped running in course when I realized most of the detail was in the crust. I switched them over to vibratory to finish up. They are dry and good example of how this opaque form of micro silica polishes so well. The vast majority of rocks in south central Texas are covered with a mustard color chert like coating or white lime, like the big one that I posted yesterday. Only one out of 20 minimum has any character underneath. Most of them end up in my yard where they look nice when it rains.

I stopped this one when I got to a layer of clear chalcedony between the layers of chert and Jasper. It started to get some spalls so I polished it to see how it would look. Yup, worth it again. I’ll probably continue with it gently in a 3 pound tumbler at some point.

That is a nice one!

Then there’s this thing. The size of a large baseball and nearly as round. As usual, it was solid, mustard yellow and very heavy. After two weeks of tumbling in course, all the yellow was disappearing, leaving the yellow swirl on top of what I believe is Texas red Jasper. So I stopped tumbling and course and immediately tried to polish it. But it still has a ton of micro pits packed with AO. Man, it’ll look so nice when I finally get it shining. I just need to tumble it for another week or two or three in say, 220 SiC, then try the slow polish build up again. Trial and error is one of my favorite parts of this hobby so all good.