This brick is one of the fire-brick once used on the charcoal ovens of Nevada.
I layered about 1/2" covering of plaster of Paris and carved an Egyptian figure in the surface. After coloring a bit here and there I put it out by the back door. Let's see that was 2005 but it's in good enough shape for the patio.
The weather has been so nice I've been doing a bit of clean-up. Also found in a pile of debris out by the back fence an old plaster mold I made back in 1995.
It's cleaned up now and sitting under a 100watt light. When it's dry I'll cast a new garden plaque.