Walk into a well-designed room and your eye often lands on something dark and quietly textured: a fireplace surround, a slim shelf bracket, a table base. Not painted, not quite black, with faint swirls of blue and brown. That's blackened steel, and it has become one of the most loved materials in contemporary interiors. It sits beautifully against timber and stone, and every piece carries its own unqiue variations.

What is it?

Blackened steel is mild steel whose surface has been turned into a thin layer of dark iron oxide, then sealed with wax. The colour isn't a coating; it's the steel itself, changed at the surface. The oxide layer is porous and gives little protection on its own. The wax does the real work, soaking in to keep moisture out and leaving a soft satin finish you want to touch.

Where it shines

• Furniture: table bases, benches and console frames, where a thin steel line carries a heavy timber top.
• Fireplaces: surrounds, hearth plates and firewood stackers, which make a pile of logs a feature.
• Shelving and joinery: brackets, ledges and balustrades that sharpen a room's lines.
• Hardware: handles, hinges and curtain rods, an easy way to bring the finish in.

Living with it

1. Dust with a dry, soft cloth; avoid sprays and cleaners, which strip wax.
2. Wipe spills straight away, as standing water causes rust spots.
3. Re-wax every three to six months: a thin coat, let it haze, then buff.
4. Rub any small rust spot with steel wool, wipe clean and re-wax.
5. Keep it indoors and away from constant damp.