Although the exact origins of this technique are not known, pots  showing this effect began showing up about 30 years ago. 

“This decorating method utilizes burnishing techniques developed by Pueblo tribes of the Southwest US where a thin clay slip known as terra siglatta is applied to the unfired ware before using pieces of polished agate to burnish the pottery surface to a shine. Pots are then fired but removed from the kiln while still extremely hot. Strands of horse hair laid across hot pieces leave a linear design carbon-trapped into the still vulnerable slip surface.”

The golden colored pots are sprayed with a iron solution while still hot. After the residue is cleaned from the surface of the pots, they are waxed and polished.

Like raku, these pots are not watertight and  should be kept out of direct sunlight.