Amethyst
Amethyst is the purple variety of quartz and February's birthstone. It is hard enough for everyday jewellery, but its colour can fade if you leave it in strong sunlight or heat, so a little care keeps the purple deep.
Key Takeaways
- Amethyst is purple quartz and rates 7 on the Mohs hardness scale, the same as all quartz, which makes it a sensible choice for everyday rings and jewellery (American Gem Society).
- It is the February birthstone (GIA).
- Its main weakness is light and heat: prolonged strong sunlight or high temperatures can fade the purple, and that fade is permanent (GIA).
- Clean it gently with warm water and mild dish soap. Skip steam cleaning and sudden temperature swings (GIA).
- Colour, not size, drives the price. A deep, even purple is worth more than a big pale stone.
How durable is amethyst?
Amethyst sits at 7 on the Mohs hardness scale, the same hardness as every other type of quartz, which is hard enough to stand up to daily wear in a ring or bracelet (American Gem Society). For reference, that puts it below the harder engagement-ring stones like sapphire and ruby but well above soft, scratch-prone materials. A 7 means everyday dust and grit — which contains quartz itself — won't easily scratch it, though over years of hard wear the facet edges can dull and benefit from a repolish.
Where amethyst differs from the really tough stones is light and heat. Mohs measures scratch resistance, not how a stone reacts to sun or temperature. Amethyst's purple comes from iron and natural irradiation in the crystal, and that colour can be undone. The GIA notes that some amethyst fades with prolonged exposure to strong light, and high heat can lighten or remove the colour too. So it is durable in the everyday sense, but it is not a stone to leave baking on a sunny windowsill or to wear day after day at the beach.
The colour grades: from pale lavender to deep Siberian purple
Amethyst runs from a light pinkish violet right through to a deep purple that can read more blue or more red depending on the light (American Gem Society). Colour is the whole game with this stone. The most prized material shows a strong, saturated reddish purple with flashes of red and blue — the trade has long called the top grade "Deep Russian" or "Siberian," after the historic mines (GIA).
A couple of buying tips I give people across the counter: avoid stones with a brownish or rusty tint, and be wary of colour that is too dark, because very deep amethyst can read almost black in dim light and lose its glow (American Gem Society). The cut matters as much as the rough colour — a well-cut stone spreads the purple evenly across the face rather than pooling it in the centre. Because good amethyst is relatively abundant and affordable, you can hold out for a colour you genuinely love rather than settling.
One note on treatments: a lot of amethyst is heat-treated, and heating can lighten overly dark stones. Heat is also used to turn amethyst into citrine or a green stone called prasiolite (GIA). Heat treatment is standard and accepted, but it's worth knowing your stone has a thermal history — it's part of why heat needs respecting.
Wearability: where amethyst works and where it doesn't
For rings, earrings, pendants, and bracelets worn normally, amethyst is a comfortable, easy-going choice. A 7 hardness handles the knocks of daily life, and the price lets you go bigger than you could with a sapphire or ruby for the same budget. It's a favourite for February birthstone pieces and for anyone who simply loves purple.
The thing to plan around is light exposure over the long haul. A ring you wear gardening every sunny afternoon, summer after summer, can slowly lose depth of colour. A pendant you wear out in the evening and store in a drawer will hold its purple for a lifetime. If you want a purple stone for an engagement ring or something that lives on your hand in all weathers, a purple sapphire is the more bulletproof option — we get into the trade-offs in our guide to Beyond Diamonds: Alternative Stones.
Amethyst vs. other coloured stones at a glance
| Stone | Mohs hardness | Main vulnerability | Everyday-ring friendly? |
|---|---|---|---|
| Amethyst | 7 | Fades in strong light / heat | Yes, with shade-and-store care |
| Sapphire | 9 | Very few; extremely tough | Yes — ideal |
| Ruby | 9 | Very few; extremely tough | Yes — ideal |
| Emerald | 7.5–8 | Brittle; inclusions, oil loss | With care |
Hardness values per the GIA and the American Gem Society. Note that sapphire and ruby are the same mineral (corundum) and share the same Mohs 9, while emerald is harder than amethyst on paper but more brittle in practice.
How to care for amethyst and keep it from fading
The good news is the care routine is simple. The GIA recommends cleaning amethyst with warm water and a mild dish soap, working gently with a soft brush. Two things to avoid: steam cleaning and any sudden change in temperature, because a thermal shock can crack the stone, and prolonged high heat can lighten or remove its colour.
To protect the purple specifically:
- Store it in the dark. Keep amethyst in a box or pouch rather than on a sunny shelf. Long stretches of direct sun are what cause the fade.
- Take it off for sun-heavy days. Gardening, beach days, long drives with your hand on the wheel in the sun — these are the situations that add up over years.
- Keep it away from heat sources. Don't leave it near a radiator, stove, or in a hot car.
- Clean by hand. Warm soapy water and a soft brush, then dry it. The GIA notes ultrasonic cleaners are usually safe for amethyst, but skip them if the stone has been dyed or fracture-filled — and steam cleaning is best avoided either way.
On our bench in Coquitlam we repolish amethyst that has gone a little dull on the facet edges, and we reset stones into new mountings when an old setting wears out — but we can't bring colour back once it has faded in the sun, which is exactly why the storage habit matters. If you're weighing amethyst against other coloured stones for a particular piece, our full Gemstone Guide: Durability, Colour & Care, Stone by Stone lays out the hardness and care for each side by side.
Frequently Asked Questions
Is amethyst hard enough for an everyday ring?
Yes. Amethyst is a 7 on the Mohs hardness scale, the same as all quartz, which the American Gem Society considers a good option for jewellery. The bigger thing to manage isn't scratching — it's keeping the stone out of prolonged strong sunlight so the colour doesn't fade.
Does amethyst really fade in the sun?
It can. The GIA notes that some amethyst fades with prolonged exposure to strong light, and the change is permanent. Normal wear is fine; it's the long, repeated sun exposure — and high heat — that gradually pales the purple. Storing the piece in a box or drawer prevents this.
What colour of amethyst is most valuable?
A deep, saturated reddish purple with flashes of red and blue — the grade the trade calls "Deep Russian" or "Siberian" (GIA). Avoid brownish tints and stones so dark they read black in low light. Because quality amethyst is affordable, you can be picky about colour.
How do I clean amethyst safely?
Warm water with a mild dish soap and a soft brush, as the GIA recommends. Don't steam-clean it and don't expose it to sudden temperature changes, which can crack the stone. Ultrasonic cleaners are usually safe for plain amethyst, but skip them if the stone has been dyed or fracture-filled.
What month is amethyst the birthstone for?
February. Amethyst is the modern February birthstone (GIA), which is a big part of why it's such a popular gift stone.
Is amethyst usually treated?
Often, yes. Much amethyst is heat-treated, a standard and accepted practice that can lighten overly dark stones, and heating can also convert amethyst into citrine or green prasiolite (GIA). Knowing a stone has been heated is one reason to keep it away from further high heat at home.