Gem library
Rhodonite
The pink silicate veined with black
Rhodonite is a pink manganese silicate, almost always crossed by black manganese-oxide veins that trace graphic networks. Harder and tougher than rhodochrosite, it is the true pink ornamental stone of lapidaries.
- Hardness (Mohs)
- 5.5 – 6.5
- Density
- 3.40 – 3.76
- Crystal system
- Triclinic
- Refractive index
- 1.711 – 1.752
- Cleavage
- Perfect on {110} and {110}
Mineralogical identity
- Family
- Silicates — inosilicates, pyroxenoid group
- Species
- Rhodonite
- Chemical formula
- MnSiO₃ (Mn,Fe,Mg,Ca)SiO₃
- Crystal system
- Triclinic
- Classification
- Semi-precious stone (ornamental rock)
- Rarity
- Common
- Indicative price
- €0.30 – 6/ct
Etymology
From the Greek rhodon, the rose, for its colour.
Physical & optical properties
- Hardness (Mohs)
- 5.5 – 6.5
- Density
- 3.40 – 3.76
- Refractive index
- 1.711 – 1.752
- Birefringence
- 0.010 – 0.014
- Cleavage
- Perfect on {110} and {110}
- Fracture
- Splintery to conchoidal
- Lustre
- Vitreous to pearly
- Diaphaneity
- Translucent to opaque
- UV fluorescence
- None
- Pleochroism
- Weak
- Colours
- pink, salmon pink, pink and black
Formation, geology & history
Metamorphic formation
Rhodonite forms by metamorphism of manganese-rich sediments, often at the contact of ore deposits. Divalent manganese occupies sites in the chain structure of silicate tetrahedra, which accounts for its stable pink colour. The characteristic black veins are secondary manganese oxides (pyrolusite, todorokite) that penetrated the cracks after formation: they trace dendritic networks, marbling and sometimes patterns so crisp they look like ink landscapes. The pink-and-black contrast made its reputation, to the point that plain veinless material is considered less interesting.
The Ural workshops
The deposits of Malo-Sedelnikovo, near Yekaterinburg, were discovered in the early nineteenth century and supplied the Russian imperial workshops with blocks weighing several tonnes. Tsar Alexander II had his wife Maria Alexandrovna's sarcophagus carved from it, in the Peter and Paul Cathedral: seven tonnes of rhodonite in a single piece, one of the largest objects ever cut from an ornamental stone. Basins, columns and table tops were also made from it. The Russians called the stone orlets, «eagle stone», after a belief that eagles left fragments of it in their nests.
Lapidary use
Its hardness of 5.5-6.5 makes it workable as cabochons, beads, pebbles and turned objects, but its perfect double cleavage calls for care: blocks split and polishing can tear flakes at grain boundaries. Australian material from Broken Hill is renowned for its strong colour. A few rare transparent rhodonite crystals, from Brazil and Japan, have been faceted for collections: these are pieces of the greatest rarity, hardly exceeding a few carats.
How to recognise it
- Dendritic black veinsThe black network of manganese oxides on a pink ground is the rhodonite signature. Rhodochrosite, by contrast, is banded with white.
- No effervescence in acidA silicate, not a carbonate: vinegar produces no reaction, unlike rhodochrosite.
- Hardness 5.5-6.5It resists a knife and just scratches glass — markedly harder than rhodochrosite (4) and dyed marble (3).
Imitations, treatments & confusions
- Confusion with rhodochrositeThe commonest. Test with acid (rhodochrosite fizzes) and hardness (rhodonite resists a knife).
- Dyed marble or howliteFar softer, dye that bleeds with acetone, no natural dendritic black veining.
- Reconstituted resinVein patterns too regular and repetitive, lightness, plastic smell on a hot point.
Deposits & origins
Russia (Urals, Malo-Sedelnikovo — the historic rhodonite of the imperial workshops), Australia (New South Wales, Broken Hill), Sweden, Brazil, Madagascar, Peru, Japan, United States (Massachusetts, where it is the state gem)
Care & precautions
- Brief rinsing in warm soapy water, dried at once. Avoid prolonged soaking.
- No salt or acids, which attack the manganese oxide veins.
- No ultrasonic cleaning: perfect double cleavage makes the stone sensitive to vibration.
- Prolonged sun exposure can slightly fade the pink; prefer shade.
Traditions & crystal healing
- Chakras
- Heart
- Zodiac signs
- Taurus · Libra
- Element
- Earth · Water
Tradition makes it a stone of reconciliation and forgiveness, associated with healing relational wounds. Its mixture of pink and black is read as accepting both faces: it is recommended for periods of relational grief rather than the beginning of a story.
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
Rhodonite or rhodochrosite?
Rhodonite is veined with black, hard (5.5-6.5) and inert in acid. Rhodochrosite is banded with white, soft (4), and fizzes in vinegar.
Can it be worn every day?
As a pendant or earrings, yes. As a ring, with reservations: its double cleavage makes it brittle despite decent hardness.
Does transparent rhodonite exist?
Yes, but it is extremely rare: a few facetable crystals from Brazil and Japan, of a few carats at most, reserved for collections.