Why your diamond looks dull, and the five-minute fix

A diamond that has lost its sparkle is usually not damaged. It is dirty in a specific place most people never clean.

What actually happens

A diamond gets its fire by taking light in through the top and bouncing it back out. That bounce happens on the underside of the stone — the pavilion, the part sitting down inside the setting.

Hand cream, soap and skin oils build up there. Once that surface is coated, light passes straight through instead of reflecting, and the stone goes flat and grey.

The top can look perfectly clean while this is happening, which is why people assume the stone is at fault.

The fix

1. Warm water, a drop of plain washing-up liquid.
2. Soak for fifteen minutes. This does most of the work.
3. Brush gently behind and underneath the stone with a soft toothbrush. Behind is the part that matters.
4. Rinse, and dry with a lint-free cloth.

Do it over a bowl, not an open drain.

Every few weeks is plenty for a ring worn daily.

What not to do

• No toothpaste. It is abrasive and will scratch gold.
• No bleach or chlorine. Chlorine attacks the alloys in gold and can weaken the prongs holding your stone.
• No ultrasonic cleaner at home for anything with a fragile setting, an emerald, or a treated stone. It can shake stones loose.

Daily habits that matter more than cleaning

• Jewellery on last, off first. After perfume and hand cream, before washing up.
• Take rings off for the gym. Bar work bends bands out of round faster than anything else.
• Store pieces separately. A diamond is the hardest natural substance there is, which means it will happily scratch every other piece in the box.

Once a year

Have the setting checked. Prongs wear down slowly and give no warning — the first sign is usually a stone that has already gone.

We do this free for anything bought from us. It takes ten minutes and it is the cheapest insurance there is.