We have written on this blog about recovering gold from sources like printed circuit boards, cell phones, remote-control devices, and digital cameras.

Today, let’s look at other sources of recyclable gold scrap that you might have overlooked.

We’ve already written about pink gold, rose gold, white gold, and even green gold on the Specialty Metals blog. (See related posts below.) We thought we’d seen just about every color, then we found an article entitled “What Can Make a Piece of Gold Turn Blue?” that Esther Inglis-Arkell wrote for io9.com. 

You have probably seen niello without knowing what it was. It looks like black enamel that has been painted into the indentations around geometric patterns on the surface of decorative silver belt buckles, goblets, candlesticks and other objects. But niello isn’t paint. It is actually a compound made of silver, sulphur and other chemicals.