Found At The Nsr

[newton1]

Forgive me because this is not a fossil.I found this in the North Sulfer River bottom in Texas. It appears to look like red sandstone on the inside and has black crystals formed on the outside. It is heavy. Does anyone know what this could be?

Thanks,

Chris

Edited October 14, 2009 by newton1

[MikeD]

I'm thinking calcite, but I'm no expert.

[CreekCrawler]

I was thinking Calcite too,but the inside has me a bit puzzled

[grandpa]

"Very heavy" - My money's on Barite.

[JohnJ]

grandpa may be onto something...see if it bubbles in vinegar or muriatic acid (taking all precautions). If it does and you can scratch it easily, it's probably calcite. The geology of the area doesn't involve a lot of quart, but there is a lot of calcite.

Calcite specimens

[Bear]

....or perhaps gypsum, which also crystallizes out like that. Would need to get a better look at the black crystals.

[tracer]

there is definitely a lot of evaporitic mineral in the nsr. having said that, what i'm primarily seen there is yellow slickenside calcite and yellow dogtooth calcite in septaria.

can't say that i've seen a rock there like the one pictured here. it's pretty cool looking.