Kala Aqeeq: Black Agate

Kala Aqeeq is black chalcedony, often sold as black onyx when it shows a white band. Its appeal is simple: a dense, mirror-polished black that looks good with silver, gold or steel and suits almost any outfit.

A word on colour treatment

We would like you to know this before you buy. Natural, solid black agate is uncommon. Most black agate in the world market has been coloured by a centuries-old process: grey agate is soaked in a sugar solution and then treated with acid and heat, which leaves carbon in the stone's pores and turns it black. The colour is permanent and the stone is still agate. It is simply not its original colour. The page for each stone says what we know of its treatment.

When choosing, look for an even, deep black with no brownish or grey patches when held to a strong light. The polish should be glassy, with no orange-peel texture. Flat-topped ovals and rectangles are ideal for engraving names or calligraphy, while domed cabochons give a softer shine.

In Pakistan black Aqeeq is a long-standing choice for men's rings, worn by many as a matter of tradition and faith. It also turns up in prayer beads and cufflinks. We respect those customs and leave belief to you.

Hardness 6.5 to 7 and a tight, tough structure make black agate one of the most durable stones in the shop. It shrugs off daily wear in a ring. Fine scratches show more easily on black, so store it separately and clean it with a soft damp cloth.