Gem library
Kunzite
The evening spodumene
Kunzite is the pink to lilac variety of spodumene, a lithium mineral. It offers a colour of rare delicacy and often substantial crystals, but it carries two weaknesses: perfect cleavage in two directions, and a colour that fades in light.
- Hardness (Mohs)
- 6.5 – 7
- Density
- 3.15 – 3.21
- Crystal system
- Monoclinic
- Refractive index
- 1.660 – 1.676
- Cleavage
- Perfect on {110}
Mineralogical identity
- Family
- Spodumene — pyroxene group (inosilicates)
- Species
- Spodumene
- Variety
- Kunzite
- Chemical formula
- LiAlSi₂O₆
- Crystal system
- Monoclinic
- Classification
- Semi-precious stone
- Rarity
- Uncommon
- Indicative price
- €15 – 120/ct
Etymology
Named in 1902 after George Frederick Kunz, chief gemmologist at Tiffany & Co., who first described it from specimens found at Pala, California.
Physical & optical properties
- Hardness (Mohs)
- 6.5 – 7
- Density
- 3.15 – 3.21
- Refractive index
- 1.660 – 1.676
- Birefringence
- 0.014 – 0.016
- Cleavage
- Perfect on {110} — two directions at 87°, very fragile
- Fracture
- Uneven, splintery
- Lustre
- Vitreous to pearly on cleavages
- Diaphaneity
- Transparent
- UV fluorescence
- Weak
- Pleochroism
- Distinct
- Colours
- pink, lilac, violet, mauve
Formation, geology & history
Formation and geology
Spodumene is a lithium pyroxene that crystallises in rare-element granitic pegmatites alongside beryl, tourmaline and lepidolite. It forms flattened prisms, deeply striated lengthwise, which reach spectacular sizes: the Black Hawk Mine in South Dakota yielded crystals over twelve metres long — the largest gem crystals ever recorded. Kunzite's pink comes from manganese; the chromium-bearing green variety is called hiddenite, and yellow and colourless spodumene also exist.
The evening stone
Kunzite is photosensitive: prolonged exposure to daylight, and still more to ultraviolet, fades its colour irreversibly. Dealers call it the «evening stone» for that reason, and advise wearing it at night or under soft lighting. The process is slow — measured in months or years — but real, and it explains why an old collection kunzite is often paler than when it was mined. Part of the market's colour is in fact produced or reinforced by irradiation, a treatment whose stability is precisely the poorest.
A difficult cut
Few gems give lapidaries so much trouble. Perfect double cleavage at 87° means the stone can part under the pressure of the wheel, and distinct pleochroism forces the table to be oriented perpendicular to the c axis to capture the best pink — at a considerable cost in weight. Which is why kunzite is almost always cut as large, deep stones whose colour reads through the thickness. A well-cut twenty-carat kunzite is a piece of virtuosity, and its price pays the cutter as much as the stone.
How to recognise it
- Longitudinal striationsIn the rough, spodumene shows a flattened prism covered in deep parallel striations — absolutely characteristic. Look for them on the girdle of cut stones too.
- Pink-to-colourless pleochroismRotate the stone: kunzite shifts from a clear pink along the c axis to a very pale, almost colourless pink seen sideways. This sharp contrast is one of its best signatures.
- Pearly cleavageUnder the loupe, incipient cleavage appears as flat, faintly pearly surfaces, often on the girdle. That pearly sheen on straight planes belongs to spodumene; morganite has none.
Imitations, treatments & confusions
- Morganite and kunzite confusedBoth are pale pink pegmatite stones cut in large volumes. Kunzite is denser (3.2 against 2.8), far more strongly pleochroic, and carries a pearly cleavage that morganite does not show.
- Pink glassAs always, the colour is too even, round bubbles betray it, pleochroism is absent and the stone feels warm. Glass never imitates the double pearly sheen of cleavage.
- Irradiated kunziteIrradiation intensifies or creates the pink. It is not illegal, but the resulting colour is often the least stable of all: it can fade within weeks of light exposure. A deeply saturated lilac at a low price should raise a question.
Deposits & origins
Afghanistan (Nuristan, Laghman — the finest colours), Brazil (Minas Gerais), Madagascar, Pakistan (Kunar), Myanmar, United States (Pala and Mesa Grande, California)
Care & precautions
- Gentle cleaning, warm water and a soft cloth only. No brush, no pressure: cleavage gives way easily.
- Never ultrasonic or steam — kunzite is one of the gems jewellers refuse to put in a machine.
- Store away from light, in an opaque pouch: it is the only way to keep the colour long term.
- Reserve it for pendants and earrings; in a ring, fragility to knocks becomes a real problem.
Traditions & crystal healing
- Chakras
- Heart · crown
- Zodiac signs
- Taurus · Scorpio · Pisces
- Element
- Water · Air
- Month
- February
Crystal healing places kunzite among the stones of unconditional love and emotional release: it is said to soothe grief, unknot tension in the solar plexus and make tenderness easier to express. Its nature as an evening stone has fed the idea of nocturnal use, slipped under a pillow or set on a bedside table.
The virtues described here belong to tradition and cultural heritage. They are in no way medical advice and never replace a consultation.
Frequently asked questions
Does kunzite really lose its colour?
Yes. It is its chief weakness, and it is irreversible. The process is slow under household lighting, fast in direct sun or under UV. Stored in the dark and worn in the evening, a kunzite keeps its hue for decades.
Can it be set in a ring?
Technically yes, but perfect double cleavage makes the operation risky for the setter and the stone vulnerable afterwards. If you insist, choose a closed bezel and an evening ring, not a wedding band.
How does it differ from morganite?
Different minerals: kunzite is a lithium spodumene, morganite a beryllium beryl. Kunzite is denser, more pleochroic, more fragile and light-sensitive; morganite is harder and far easier to live with.