🔎 UNIDENTIFIED What is this slab concretion?

[Thatguy51]

My buddy was digging up a natural spring for a pond and has found several of these reddish orange sandstone/sedimentary rock slabs all about 5 to 7 inches thick and super heavy. This one in the picture is 4 foot by 3 foot and 5 inches thick. Would love to know what exactly it is and if they are worth anything.

 

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[Mud Hut]

My guess is "moqui marbles" which are iron oxide concretions in sandstone.

 

[Thatguy51]

My guess is "moqui marbles" which are iron oxide concretions in sandstone.

Thank you for identifying it for me.

 

[Red-Coat]

Welcome to Tnet.

Not 'Moqui marbles' I think, which are a particular kind of iron oxide/sandstone concretion... but botryoidal hematite.(and weathered).

Google both and you'll see the difference in form.

 

[blauer]

I agree with Red-coat: botryoidal hematite.

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[Thatguy51]

Thank you for the time and identification that you all have given me. Any idea if they are worth anything?

 

[Red-Coat]

Thank you for the time and identification that you all have given me. Any idea if they are worth anything?

Not much, unfortunately. This 5.5 inch specimen in my collection cost £5 ($6,50) from a 'rock & gem' shop, although that was about 20 years ago,

Any value is compoundly increased in larger specimens, but constrained by the fact that rock and mineral collectors generally prefer to have cabinet-sized specimens.