Acid- no reaction
scratches with knife, but not with coin
white streak, black & brown on outside
brown on ground side with dimpling and voids all over, found in Bridgeport,
Tx near Trinity River not typical of area-lime stone, is bedrock around here, we were picking up petrified wood when this was found. The rock in opaque, fine grained dark area is 10-12 mm by 5.5 mm, polishes well. non magnetic and non metallic.