Gem library
Sugilite
Magenta from the Kalahari
Sugilite is a lithium-manganese silicate of a deep magenta violet that belongs to it alone. Gem-quality material comes from a single South African mining field, briefly worked in the 1980s, and most of what circulates today comes from old stock.
- Hardness (Mohs)
- 5.5 – 6.5
- Density
- 2.74 – 2.80
- Crystal system
- Hexagonal
- Refractive index
- 1.607 – 1.610
- Cleavage
- Indistinct
Mineralogical identity
- Family
- Sugilite — cyclosilicate group (osumilite)
- Species
- Sugilite
- Chemical formula
- KNa₂(Fe,Mn,Al)₂Li₃Si₁₂O₃₀
- Crystal system
- Hexagonal (massive aggregate)
- Classification
- Collector's mineral · ornamental stone
- Rarity
- Rare
- Indicative price
- €20 – 200/ct
Etymology
Named after Ken-ichi Sugi, the Japanese petrologist who discovered it in 1944 on Iwagi island. The correct pronunciation follows the Japanese — «soo-gee-lite» — not the English.
Physical & optical properties
- Hardness (Mohs)
- 5.5 – 6.5
- Density
- 2.74 – 2.80
- Refractive index
- 1.607 – 1.610
- Birefringence
- 0.003
- Cleavage
- Indistinct
- Fracture
- Uneven to splintery
- Lustre
- Vitreous to waxy
- Diaphaneity
- Opaque, translucent in thin section
- UV fluorescence
- None
- Pleochroism
- None
- Colours
- violet, magenta, purple, pink
Formation, geology & history
A discovery in two stages
Ken-ichi Sugi identified sugilite in 1944 in a syenite on the Japanese island of Iwagi: a yellow-brown mineral of no ornamental interest, formally described only in 1976. Everything changed in 1979, when miners in the Kalahari manganese field of South Africa opened, at 3,400 metres depth, a vein of massive sugilite of astonishing magenta. Manganese, abundant there, replaced iron and produced that unique colour. The main vein was exhausted within a few years; the Wessels and N'Chwaning mines now yield it only very sporadically, which explains the steady rise in prices since the 1990s.
A colour without equal
Sugilite's violet is not amethyst's, nor charoite's. It is a dense magenta, almost fuchsia in the finest pieces, ranging from pale pink-violet to the deep purple called «gel sugilite» when it turns translucent. That gel quality, the rarest and most expensive, transmits light over one or two millimetres and trades by the carat like a gem. Ordinary material is opaque, often zoned, mixed with black braunite or pink manganese, and sells by the gram as cabochons and plaques.
A stock market
Sugilite illustrates a phenomenon rare in gemmology: a stone whose supply no longer depends on mining but on reserves accumulated by a handful of dealers in the 1980s. Prices therefore follow a collecting logic rather than a production one, and fine pieces change hands among specialists. That situation attracts imitations: coloured resins, powder agglomerates, and above all charoite or lepidolite sold under its name. At this price level, documented origin counts as much as appearance.
How to recognise it
- Plain magentaSugilite is a dense, relatively uniform magenta violet, with no fibres or swirl. A swirling silky violet is charoite; a shiny micaceous lilac, lepidolite.
- The Kalahari companionsSouth African pieces often come with black braunite veins, pink manganese patches or white calcite. That assemblage is characteristic of the deposit.
- Moderate hardness, modest weightAt 5.5-6.5 it is scratched with difficulty by steel but yields to quartz, and its density of 2.77 makes it light in the hand. A heavy violet stone is not sugilite.
Imitations, treatments & confusions
- Charoite and lepidolite confusedBoth are violet and affordable. Charoite is fibrous and swirled, lepidolite micaceous and flaky. Sugilite is massive and plain: structure alone settles it.
- Resin and agglomeratesPowders of sugilite or anything else bound with resin. Far lighter, warm to the touch, and a hot point applied in a hidden area releases a smell of plastic.
- Glass and dyed «sugilite»Some cabochons are chalcedony or quartzite dyed magenta. The dye concentrates in fissures, visible under the loupe as a darker network on a lighter ground.
Deposits & origins
South Africa (Wessels and N'Chwaning mines, Kalahari manganese field, Northern Cape — the only gem-quality source, effectively exhausted), Japan (Iwagi, type locality, non-gem), Canada (Quebec), Italy, India, Australia, Tajikistan
Care & precautions
- Barely soapy warm water and a soft cloth; quick rinse, immediate drying.
- Avoid ultrasonic and steam cleaning, particularly on zoned or fractured pieces.
- Do not leave it long in the sun: the manganese violet can fade. Avoid all acids.
- Store separately, away from light and from hard stones that would scratch it.
Traditions & crystal healing
- Chakras
- Third eye · crown
- Zodiac signs
- Scorpio · Sagittarius · Virgo
- Element
- Ether
- Month
- February
Sugilite reached the market at precisely the moment Western crystal healing was taking shape, and it holds a notable place there: presented as the stone of the «violet ray» and of spiritual protection, it is linked to the third eye and the crown. It is credited with easing deep sorrow and helping forgiveness. No ancient tradition concerns it: its symbolism is less than fifty years old.
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
Why is sugilite so expensive?
Because the only gem-quality source was exhausted within a few years in the 1980s, and the market now lives on stock. The price reflects genuine scarcity, not manufactured demand.
Sugilite or charoite?
Charoite is fibrous, swirled, turbulent and comes from Siberia; sugilite is massive, plain, magenta and comes from South Africa. By eye, structure separates them immediately.
Does translucent sugilite exist?
Yes, the so-called «gel» quality, the most sought after: the violet deepens and transmits light over one to two millimetres. It sells by the carat, several hundred euros for the best pieces.