How to Clean and Maintain Gemstone Jewellery: A Stone-by-Stone Guide

Why Gemstone Care Is Different from Metal Care

Cleaning sterling silver is straightforward — it is a metal with predictable properties. Gemstones are far more varied. Each stone has its own hardness, porosity, sensitivity to heat, and reaction to chemicals. What is perfectly safe for an amethyst could damage an apatite.

Understanding your gemstones is the first step to keeping them beautiful for a lifetime.

The Mohs Hardness Scale: Your Quick Reference

The Mohs scale rates mineral hardness from 1 (softest) to 10 (hardest). As a rule, stones rated 7 and above can tolerate more vigorous cleaning, while softer stones require gentler methods.

• Topaz — 8 (very durable)
• Amethyst — 7 (durable)
• Tiger's Eye — 7 (durable)
• Aventurine — 7 (durable)
• Kyanite — 4.5–7 (varies by direction)
• Apatite — 5 (moderate, handle with care)
• Hematite — 5.5–6.5 (moderate)

Universal Cleaning Rules

These apply to virtually all gemstone jewellery:

1. Never use ultrasonic cleaners unless you are certain the stone can handle it. Many gemstones can crack or fracture from ultrasonic vibrations
2. Avoid steam cleaning — sudden temperature changes can cause thermal shock in many stones
3. No harsh chemicals — bleach, ammonia, and alcohol-based cleaners can damage both stones and their settings
4. Dry thoroughly — moisture left in settings or around porous stones can cause long-term damage
5. Pat, do not rub — aggressive rubbing can scratch softer stones

Stone-by-Stone Cleaning Guide

Amethyst (Hardness 7)

Amethyst is relatively durable but sensitive to prolonged heat and direct sunlight, which can fade its colour over time.

Safe to use: Warm water with mild soap, soft brush, soft cloth

Avoid: Prolonged sun exposure, ultrasonic cleaners, steam, sudden temperature changes

Tiger's Eye (Hardness 7)

A hardy stone thanks to its quartz base. Its chatoyant (cat's eye) effect comes from fibrous structures that are best maintained by avoiding harsh chemicals.

Safe to use: Warm soapy water, soft cloth, gentle brushing

Avoid: Ultrasonic cleaners, chemical solvents, prolonged soaking

Apatite (Hardness 5)

Apatite is one of the softer gemstones used in jewellery and requires extra care. It scratches relatively easily and is sensitive to acids and heat.

Safe to use: Cool to lukewarm water, very mild soap, extremely soft cloth

Avoid: Hot water, ultrasonic cleaners, any acidic solutions, rough contact with harder stones

Kyanite (Hardness 4.5–7)

Kyanite has a unique property — its hardness varies depending on the direction of the crystal. Along the blade it can be as soft as 4.5, while across it measures up to 7. This makes it important to handle gently.

Safe to use: Lukewarm water, mild soap, soft cloth with light pressure

Avoid: Ultrasonic cleaners, steam, mechanical cleaning, rough handling

Hematite (Hardness 5.5–6.5)

Hematite has a beautiful metallic lustre but can rust if exposed to prolonged moisture, as it is an iron oxide mineral.

Safe to use: Quick wipe with a barely damp cloth, dry immediately

Avoid: Soaking in water, ultrasonic cleaners, humid storage conditions

Aventurine (Hardness 7)

A variety of quartz, aventurine is relatively tough and maintains its sparkle well. Its inclusions (which create the shimmery aventurescence effect) are stable.

Safe to use: Warm soapy water, soft brush, soft cloth

Avoid: Ultrasonic cleaners, extreme temperature changes, harsh chemicals

Topaz (Hardness 8)

One of the hardest gemstones in common use, topaz is durable but has perfect cleavage — meaning it can split along a plane if struck sharply.

Safe to use: Warm soapy water, soft brush, soft cloth

Avoid: Sharp impacts, ultrasonic cleaners (due to cleavage risk), steam cleaning

Storage Tips for Gemstone Jewellery

• Separate softer stones from harder ones — a topaz stored against an apatite will scratch it
• Use individual pouches or compartments — soft fabric pouches prevent contact damage
• Keep away from direct sunlight — UV light fades amethyst, rose quartz, and many other coloured stones
• Control humidity — too dry and some stones can crack; too humid and hematite can oxidise

When to Seek Professional Cleaning

If a stone appears cloudy, a setting feels loose, or you notice any chips or cracks, take it to a professional jeweller. Attempting to fix structural issues at home risks further damage. An annual professional inspection is a worthwhile investment for pieces you wear regularly.