Colored gemstones require different care than diamonds. While diamonds are the hardest natural material on Earth, most colored stones are significantly softer and more vulnerable to scratches, chemicals, heat, and impact. Understanding your gemstone’s specific needs is the key to keeping it beautiful for generations.
This guide covers care by stone type, with practical advice on cleaning, storage, and what to avoid. For general jewelry care including metals, settings, insurance, and repair, see our Jewelry Care Guide.
Why Gemstone Hardness Matters
The Mohs hardness scale rates minerals from 1 (talc) to 10 (diamond) based on scratch resistance. This scale is the single most important factor in determining how to care for a gemstone. Harder stones tolerate more aggressive cleaning methods and resist scratches from daily wear. Softer stones require gentler handling.
As a general rule:
- 7 and above — safe for everyday wear in rings. Resistant to scratches from common household dust (which contains quartz at Mohs 7).
- 6 to 6.5 — suitable for earrings, pendants, and occasional-wear rings. Will scratch over time with daily ring wear.
- Below 6 — best for earrings and pendants. Too soft for rings that will see daily wear.
Mohs Hardness & Care Chart
| Gemstone | Mohs | Warm Soapy Water | Ultrasonic | Steam | Special Notes |
|---|
| Sapphire | 9 | ✓ | ✓ | ✓ | Very durable. Safe for all cleaning methods unless heavily included or fracture-filled. |
| Ruby | 9 | ✓ | ✓ | ✓ | Same durability as sapphire. Avoid ultrasonic if lead glass-filled. |
| Alexandrite | 8.5 | ✓ | ✓ | ✓ | Very durable. Safe for all cleaning methods. |
| Topaz | 8 | ✓ | ✓ | ✓ | Hard but has perfect cleavage — can split from a sharp blow. Coated topaz (Mystic) should not be ultrasonically cleaned. |
| Aquamarine | 7.5–8 | ✓ | ✓ | ✓ | Durable. Safe for all methods. Avoid prolonged heat exposure. |
| Emerald | 7.5–8 | ✓ | ✗ | ✗ | Almost always oil-treated. Ultrasonic and steam will strip oil, making inclusions more visible. Clean gently with warm soapy water only. |
| Morganite | 7.5–8 | ✓ | ✓ | ✓ | Durable beryl family. Safe for all methods. |
| Spinel | 8 | ✓ | ✓ | ✓ | Very durable and untreated. Safe for all cleaning methods. |
| Garnet | 6.5–7.5 | ✓ | Caution | ✗ | Hardness varies by variety. Avoid ultrasonic for demantoid (included). No steam. |
| Tourmaline | 7–7.5 | ✓ | Caution | ✗ | Do not use ultrasonic if the stone has visible inclusions. Avoid sudden temperature changes. |
| Citrine | 7 | ✓ | ✓ | ✗ | Quartz family. Durable. Avoid steam and prolonged sunlight (color can fade). |
| Amethyst | 7 | ✓ | ✓ | ✗ | Quartz family. Avoid heat and prolonged direct sunlight — color can fade permanently. |
| Peridot | 6.5–7 | ✓ | ✗ | ✗ | Sensitive to acids and rapid temperature changes. Never use ultrasonic or steam. |
| Tanzanite | 6–7 | ✓ | ✗ | ✗ | Beautiful but fragile. Perfect cleavage in one direction. Avoid ultrasonic, steam, and sudden temperature changes. Best in pendants and earrings. |
| Opal | 5.5–6.5 | Damp cloth | ✗ | ✗ | Contains water — can crack if dehydrated. Never soak. Wipe with a damp cloth only. Store away from heat and dry environments. |
| Pearl | 2.5–4.5 | Damp cloth | ✗ | ✗ | Extremely delicate. Wipe with a soft damp cloth after every wear. Never soak, never use chemicals. Restring annually if worn regularly. |
The Universal Cleaning Method (Safe for Most Gemstones)
For any gemstone rated Mohs 7 or above without special treatments, this method works well:
- Prepare a solution of a few drops of mild dish soap (like Dawn) in a bowl of lukewarm water — never hot.
- Soak the piece for 10 to 20 minutes to loosen buildup.
- Scrub gently with a very soft toothbrush (baby toothbrush is ideal), paying attention to the area under the stone where oils and lotion accumulate.
- Rinse under lukewarm running water. Place a mesh strainer over the drain.
- Pat dry with a soft, lint-free cloth. Allow to air dry completely before storing.
Important: Always check the chart above before cleaning. Emeralds, opals, pearls, tanzanite, and peridot all require gentler methods.
Stone-by-Stone Care Details
Sapphires & Rubies (Corundum Family)
Sapphires and rubies are the easiest colored gemstones to care for. At Mohs 9, they are second only to diamond in hardness. They tolerate warm soapy water, ultrasonic cleaners, and steam cleaning without issue. The only exception: lead glass-filled rubies should never be ultrasonically cleaned or exposed to acids (including lemon juice and vinegar), as the glass fill can deteriorate. If your ruby came with a lab report noting “glass filling,” stick to warm soapy water only.
Emeralds
Despite being Mohs 7.5–8, emeralds require the most careful handling of the “big three” gemstones. Nearly all emeralds are treated with oil or resin to fill surface-reaching fractures — this is standard practice and has been done for centuries. Ultrasonic cleaners and steam cleaners will strip this oil, making the emerald’s natural inclusions (called jardin) much more visible. Clean emeralds with warm soapy water and a soft cloth only. Avoid ammonia, alcohol, and any harsh chemical. If your emerald begins to look cloudy or dry, a jeweler can re-oil it.
Tanzanite
Tanzanite is one of the most beautiful and one of the most fragile popular gemstones. It has perfect cleavage in one direction, meaning it can split cleanly from a sharp blow. It is also sensitive to thermal shock — rapid temperature changes can cause cracking. Clean with lukewarm soapy water only. Never use ultrasonic or steam. Tanzanite is best set in pendants and earrings rather than everyday rings.
Opals
Opals are unique because they contain water — typically 3% to 10% by weight. If an opal dries out, it can “craze” (develop a network of fine cracks). Never soak opals in water or cleaning solutions. Never use ultrasonic or steam. Wipe with a soft, slightly damp cloth. Store opals in a cool place away from heat vents and direct sunlight. Some jewelers recommend placing a damp cotton ball in the storage box to maintain humidity, though this is debated. Doublet and triplet opals (layered constructions) are especially sensitive to water — moisture can seep between layers and cause a foggy appearance.
Pearls
Pearls are organic gems with a Mohs hardness of only 2.5 to 4.5 — they scratch easily and are damaged by virtually all chemicals including perfume, hairspray, cosmetics, and even perspiration. Always put pearls on last and take them off first. After every wearing, wipe with a soft, slightly damp cloth to remove body oils. Never soak pearls. Never use ultrasonic or steam. Store separately from other jewelry to prevent scratching. If pearl strands are worn regularly, have them restrung annually — the silk thread weakens over time and can break without warning.
Tourmaline
Tourmaline is reasonably durable at Mohs 7–7.5 but can be heat-sensitive. Avoid ultrasonic cleaning if the stone has visible inclusions, as vibrations can extend fractures. Clean with warm soapy water. Paraiba tourmalines are especially valuable and should be treated with extra care.
Peridot
Peridot is moderately hard (Mohs 6.5–7) but sensitive to acids and rapid temperature changes. Even mild acids like those found in some cleaning products can etch the surface. Never use ultrasonic or steam. Clean with warm soapy water only. Peridot can also be damaged by prolonged exposure to perspiration.
Aquamarine & Morganite (Beryl Family)
Both are durable stones (Mohs 7.5–8) and tolerate most cleaning methods well. Warm soapy water, ultrasonic, and steam are all safe. Avoid prolonged exposure to intense heat, which can alter color in some specimens. Aquamarines are excellent choices for everyday-wear rings due to their toughness.
What to Avoid with All Gemstones
- Bleach and chlorine — damages metals, can discolor or etch gemstones, and attacks treatments.
- Toothpaste — abrasive. Will scratch softer stones and metals.
- Sudden temperature changes — can crack many gemstones, especially tanzanite, opal, and tourmaline.
- Prolonged direct sunlight — can fade amethyst, citrine, kunzite, and some topaz over time.
- Household chemicals — remove gemstone jewelry before using cleaning products, especially anything acidic or containing ammonia.
- Hard impacts — even hard stones like sapphire can chip or crack from a sharp blow against a hard surface.
Gemstone Storage Tips
- Store each piece separately — harder stones will scratch softer ones. Keep diamonds away from all other gemstones.
- Use soft pouches or lined compartments — avoid tossing gemstone jewelry into a dish or open box.
- Control humidity for opals — avoid storing near heat sources. A moderate humidity environment is ideal.
- Keep pearls away from other jewelry — their soft surface scratches easily. Store in a separate soft pouch.
- Avoid airtight containers for opals — they need some air circulation to maintain moisture content.
Professional Care Schedule
- Every 6 months: Have a jeweler check prongs and settings on gemstone rings. Loose settings are the number one cause of lost gemstones.
- Annually: Professional cleaning for pieces you wear frequently. A jeweler can safely clean stones that are risky to clean at home.
- As needed: Re-oiling for emeralds if they begin to look drier or more included than when purchased.
- As needed: Restringing for pearl strands worn regularly.
When to Seek Professional Help
Take your gemstone jewelry to a professional jeweler if you notice:
- A stone that moves, rattles, or sits unevenly in its setting
- A prong that catches on fabric (bent or worn)
- A chip or crack in the gemstone (do not continue wearing — the damage can worsen)
- An emerald that has become noticeably cloudy or dry-looking
- Pearl strands that feel loose or have visible fraying at the knots
For more about general jewelry maintenance, repair, and insurance, visit our Jewelry Care Guide. For detailed information about gemstone types and qualities, see our Gemstone Buyers Guide and Gemstone Grading Guide.