Lowes hardware fire brick specs

I was at Lowes today with my RMH shopping list. I see they carry one fire brick. I went to customer service and he pulled up the specs and it said concrete material rated at 3000f. Is this correct from what i have read I assumed this was a specialty product to reach those temps or every one would just stop into lowes.  Of course the generic wording they have it may not actually be concrete or i dont under stand what fire brick is yet. I'm building the j tube RMH FYI

Not sure about the lowes bricks. Normally you would look for a masonry supply house.  An example is White Block in spokane valley  WA. .  Fire clay / full size fire brick / split fire brick and I think they offer insulating fire bricks as well.  Any larger town should have a similar type business.  

After a little research, I would guess that the description of Concrete Material is an error ... it's probably clay based. From Lowes website, that brick is from Oldcastle and looking at their website I could not find that specific product, but they do have sources for clay bricks. Since it is described as fire brick, I would think the 3000 degree rating is accurate. That's a good price for new, full-size fire brick. Unfortunately my local Lowes doesn't carry it.

Good luck.

Is there a test you can do to a brick to see if it will pass muster. I have cutting torches and a laser temp gun. Can I see where one melts. or is it just better to move to a known product. Would you mind sharing the link you found at Lowes to the name brand. I dont seem to be doing the correct search for it.

I actually found this forum message googling about the old castle bricks. It appears there is some thought already put into these box store bricks. https://permies.com/t/30551/Fake-fire-brick

Here is the Lowes webpage that identifies the brick as Oldcastle. It is a heavy brick, so it won't provide a lot of insulation.
https://www.lowes.com/pd/Oldcastle-Concrete-Fire-Brick/50037062

Here is the Oldcastle website:
http://www.oldcastle.com/building-products.php