Silver, plainly explained

Sterling silver is 92.5% pure silver by weight, which is why it is called 92.5. The other 7.5% is another metal, usually copper.

Pure silver is too soft for rings, clasps and chains; they bend and scratch within weeks. The small share of copper makes the metal harder without changing its colour.

That is why sterling is stamped 925: 925 parts silver in every 1,000.

A hallmark is a mark put on a piece by an assaying and hallmarking centre recognised by the Bureau of Indian Standards, after a sample of the metal is tested.

On Belli silver it has three parts: the BIS logo, the purity grade (925 for sterling silver), and a six-character HUID, a code unique to that piece.

You can check a HUID with the BIS Care app. The marks are tiny, usually inside a ring band or on a clasp tag; a loupe helps.

Silver reacts with sulphur in the air, in sweat, and in things like rubber bands, wool, eggs and onions. The result is a thin film of silver sulphide: tarnish.

Damp air speeds it up. It sits only on the surface and does not harm the metal, and pieces worn often darken least, because skin and cloth rub the film away.

Polished pieces: wash in warm water with a drop of mild soap, brush gently with a soft toothbrush, rinse, and dry completely. Finish with a silver polishing cloth.

Oxidised pieces: soap and water only. A polishing cloth or a silver dip lifts the dark finish from the recesses.

Avoid toothpaste, baking soda and kitchen scourers on any finish; they scratch.

Keep each piece dry and apart from the others, in its pouch or a small zip bag with the air pressed out.

Not in the bathroom: steam brings tarnish on fast. Take silver off to swim, as chlorine marks it, and put on perfume and lotion before your jewellery.