Steel, Carbonized (3.5e Equipment)
From D&D Wiki
Carbonized steel is an iron alloy with high carbon content. Its hardness and related physical properties are identical to normal steel, but it is charcoal gray or black in color, and totally non-reflective.
Crafting carbonized steel is a specialized skill known only to a handful of master craftsmen, primarily obsidian dwarves.
Carbonized steel armor does not apply its armor check penalty to Hide skill checks in dim light or in the presence of shadows – even if the viewer has low-light vision or darkvision. It applies the standard armor check penalty to other skill checks, and to Hide skill checks in bright light.
Metallic items made with carbonized steel are identical to normal steel items in all other respects. (Non-metallic items, obviously, cannot be made from carbonized steel.)
If the craftsman fails his skill check by 10 or more points, the materials crumble into pieces. If he fails by less than 10 points, he produces a defective product with ¼ normal hardness. A DC 20 Appraise check is required to notice the defective quality.