Where to Begin with Gemstones

Walk into any jeweller's and the colour is what hits you first — a tray of deep blue sapphires, a cluster of green emeralds, a scattering of pale pink morganite. Colour is a wonderful place to start, but it should not be the only thing guiding you. A gemstone you wear every day has to survive knocks, hand cream, washing-up and the occasional accidental scrape against a brick wall. So before you fall in love with a shade, it is worth understanding three practical things: how hard the stone is, whether it has been treated, and where it came from.

None of these details make a stone better or worse in a moral sense. They simply tell you what you are buying, how it will behave over decades, and how much care it will need.

Hardness: What the Mohs Scale Really Tells You

The Mohs scale runs from 1 to 10 and measures how well one mineral scratches another. Diamond sits at 10; talc at 1. It is a useful guide, but it is not the whole story. Hardness is about scratching, while toughness is about chipping and cracking. A stone can be hard and still brittle — emerald is a good example. A stone can be relatively soft yet surprisingly resilient.

For a ring worn daily, here is roughly where the popular choices sit:

• Diamond — 10. Extremely hard and tough, which is why it dominates engagement rings.
• Moissanite — 9.25. Nearly as hard as diamond, with even more sparkle.
• Ruby and sapphire (both corundum) — 9. Excellent for everyday wear and available in a wide range of colours.
• Spinel and topaz — 8. Spinel is a superb, often overlooked alternative; topaz needs a little more caution.
• Emerald, aquamarine, morganite — 7.5 to 8. Fine for rings, but the cut corners and inclusions make emerald more vulnerable to chips.
• Amethyst, citrine, quartz — 7. Acceptable, though they will dull over years of hard wear.
• Opal, tanzanite, moonstone, pearl — 2.5 to 6.5. Beautiful, but best saved for occasional-wear rings or protected settings.

A useful rule of thumb: for a ring worn every day, aim for 8 or above unless you are comfortable with a little extra care.

The Traditional Trio: Diamond, Sapphire, Ruby

These three have earned their reputation. Diamond remains the benchmark for brilliance and takes almost anything life throws at it. Sapphire and ruby are the same mineral, corundum, coloured by trace elements — iron and titanium for blue, chromium for red. Both are tough, take a high polish, and suit almost any setting.

Sapphires come in far more than blue: pale peach, teal, yellow, green and the sought-after padparadscha. Rubies range from a soft pinkish red to a deep, slightly purplish crimson. If you want a coloured centre stone that will still look crisp after twenty years of daily wear, these are the safest and most rewarding choices.

Emeralds, Opals and Other Softer Beauties

Emerald's colour is unmatched — a vivid, velvety green that no other stone quite replicates. Its trade-off is character: nearly every emerald contains inclusions, and jewellers call this the jardin, or garden. Those internal fractures make it more prone to chipping, so a protective setting with a bezel or corner prongs is a wise choice.

Opal is softer still and can lose moisture if stored badly; a drop of water or a damp cotton pad in its box helps. Tanzanite, with its violet-blue pleochroism, is lovely but should be worn with care. Pearl and moonstone are delicate and best kept for earrings, pendants or rings worn occasionally.

Treatments and Origin: Ask the Right Questions

Most coloured gemstones on the market have been treated, and that is normal. Heating sapphires and rubies to improve colour is an accepted practice that has gone on for centuries and is stable. What matters is that you are told.

Less straightforward treatments include fracture filling in emeralds, where oil or resin is used to disguise surface-reaching cracks, and glass filling in some rubies. These stones should never go into an ultrasonic cleaner, and they need gentler handling. Ask directly whether a stone is treated, and what with.

Origin — Kashmir, Burma, Colombia, Sri Lanka — is often used as a mark of prestige. It can affect price, but it does not guarantee beauty or durability. A well-cut stone from a less famous source will usually outshine a poorly cut one from a celebrated mine. For anything significant, request a report from a recognised gemmological laboratory.

Looking After a Gemstone Ring

Care is simpler than many people expect. Remove your ring before gardening, cleaning, swimming in chlorinated water or lifting weights, and take it off when applying hand cream or perfume. Store gemstone rings separately, in a soft pouch or lined compartment — a diamond will happily scratch a sapphire or an emerald sitting next to it in a drawer.

For diamonds, sapphires and rubies, warm water with a drop of washing-up liquid and a soft toothbrush works beautifully. Skip the ultrasonic for emerald, opal, pearl, tanzanite and any fracture-filled stone, and never use steam on them. Finally, have your prongs checked once a year by a jeweller. Most lost stones are not the stone's fault; they are the result of a claw that loosened quietly months earlier.