Home Depot used to sell / market these as “fire brick”, but they are just red clay brick and they are not designed for high-temp ovens. Even when you search “fire brick” on HD’s site, this red clay brick pops-up first.
Sure, you can line a fire pit w/ them… but as for cooking - these aren’t the brick you are looking for.
Here is more info: Fire Brick Vs. Red Clay Bricks - BrickWood Bulletin Board - BrickWood Ovens
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clay brick.