Gem library
Thulite
The pink zoisite of Norway
Thulite is the pink variety of zoisite, the same mineral that gives tanzanite in blue and the green of ruby matrices. Its colour comes from manganese, and Norway has made it its national stone.
- Hardness (Mohs)
- 6 – 6.5
- Density
- 3.10 – 3.40
- Crystal system
- Orthorhombic
- Refractive index
- 1.685 – 1.707
- Cleavage
- Perfect on {010}
Mineralogical identity
- Family
- Silicates, sorosilicates, epidote group
- Species
- Zoisite
- Variety
- Manganoan zoisite
- Chemical formula
- Ca₂Al₃(SiO₄)₃(OH) + Mn
- Crystal system
- Orthorhombic
- Classification
- Semi-precious stone (ornamental rock)
- Rarity
- Uncommon
- Indicative price
- €0.50 – 8/ct
Etymology
From Thule, the name the ancients gave the northernmost known land, often identified with Norway, where the mineral was described in 1820.
Physical & optical properties
- Hardness (Mohs)
- 6 – 6.5
- Density
- 3.10 – 3.40
- Refractive index
- 1.685 – 1.707
- Birefringence
- 0.006 – 0.018
- Cleavage
- Perfect on {010}
- Fracture
- Uneven
- Lustre
- Vitreous to pearly
- Diaphaneity
- Opaque to translucent
- UV fluorescence
- None
- Pleochroism
- Weak
- Colours
- pink, deep pink, pinkish red, white
Formation, geology & history
One family, three colours
Zoisite is a calcium aluminium silicate whose colour depends entirely on the trace element that joins it. With vanadium, heated, it becomes tanzanite, violet blue and transparent. With chromium, it gives green zoisite, well known as ruby matrix. With trivalent manganese, it turns pink and is called thulite. The same mineral, three commercial stones with no resemblance at all: a good example of what a few tenths of a percent of a colouring element can do. Thulite forms in calcium-rich metamorphic rocks, often accompanied by quartz and a little mica.
Norway's national stone
Thulite was first described in 1820 from samples at Souland, in Telemark. The deposits at Leksvik, in Trøndelag, supply the best-known ornamental material, a deep pink veined with white and grey. Norway has made it its national stone, and it turns up in local craft as in public architecture: polished thulite panels decorate several buildings in Oslo. It was exported late, and remains distinctly less known than rhodonite or rhodochrosite, which occupy the same niche of veined pink.
Working and wear
With a hardness of 6 to 6.5, thulite is far sturdier than most opaque pink stones: rhodochrosite is 3.5, rhodonite 6. It takes a bright, deep polish, is cut into cabochons, plates and objects, and stands daily wear as a pendant. Its perfect cleavage in one direction nonetheless calls for care when sawing. Trade pieces are rarely pure thulite: it is generally a rock in which pink zoisite alternates with white quartz and sometimes dark hornblende, and that contrast is precisely what makes it decorative.
How to recognise it
- Pink veined with whiteThe texture is characteristic: irregular pink patches separated by veins of white quartz. A uniform pink with no structure is not thulite.
- Hardness 6It scratches glass, which immediately rules out rhodochrosite (3.5) and dyed magnesite. A steel point does not bite it easily.
- No effervescenceA drop of dilute acid does nothing. Rhodochrosite, a carbonate, fizzes at once.
Imitations, treatments & confusions
- Rhodonite sold as thuliteVery close in appearance, but rhodonite is veined with black (manganese oxides) rather than white. Same hardness, same price: the confusion is honest.
- Magnesite or howlite dyed pinkMuch softer, veined with grey, and the dye bleeds with acetone.
- Dyed pink quartziteSold as beads. Quartzite is hardness 7, but the colouring is too uniform and the grains show under a loupe.
Deposits & origins
Norway (Leksvik and Snarum, the historic deposits), Austria, Italy, United States (North Carolina), Western Australia, Namibia
Care & precautions
- Warm soapy water and a soft brush, without worry. Rinse and dry.
- Avoid ultrasonics on veined pieces: the contact planes between zoisite and quartz behave differently.
- Takes light without fading.
- Store separately, the polish is scratched by quartz and harder stones.
Traditions & crystal healing
- Chakras
- Heart
- Zodiac signs
- Taurus · Cancer
- Element
- Earth
Associated with the heart and with kindness towards oneself, it is often recommended alongside rhodonite in Nordic handbooks. Its status as Norway's national stone gives it a strong local following. Cultural heritage, never medicine.
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
Thulite or rhodonite?
Look at the veins. Thulite is veined with white (quartz), rhodonite with black (manganese oxides). Both are pink and of similar hardness.
Can it be worn every day?
Yes as a pendant or earrings, and even as a ring if the setting protects the edges. Hardness 6 is reasonable for an opaque stone.
Is it the same family as tanzanite?
Exactly the same species, zoisite. Only the colouring element changes: manganese for pink, vanadium for blue.
Tools for this stone
Thulite: only the tools this stone actually concerns, each carrying the value read on this page.