The facts
What lumachella actually is
Lumachella is classified as a fossiliferous limestone packed with iridescent shell fragments - typically ammonite or gastropod nacre preserved in a dark carbonate matrix, with the composition Calcite CaCO3 matrix with aragonitic nacreous shell. It crystallises in the aggregate system.
Colour comes from thin-film interference in the preserved nacre gives red, green and gold flashes against a dark ground, which is also what a laboratory looks at when it is asked whether a colour is natural.
Refractive index 1.486-1.658. Specific gravity around 2.60-2.80. Cleavage: calcite cleavage in grains. Those three numbers separate it from most of what imitates it.
Where lumachella comes from
Lumachella is produced at Bleiberg and Hallstatt, Carinthia and Salzkammergut, Austria - the classic Triassic fire marble, Bastenaken, Belgium (historic) and Spain and Italy (related shell marbles).
The locality is part of the description, not a footnote — two stones of the same weight from two of these places are not the same stone.
How lumachella is treated
Polished and waxed. Historically a prized inlay and snuff-box material in 18th and 19th century Europe; current supply is very limited and most pieces on the market are antique. Occasionally confused with ammolite, which is a much thicker and more intensely coloured nacre. Not CITES.
Treatment changes value, sometimes by a multiple, so it belongs in the description before the price and not after the sale.
What lumachella is confused with
In the trade lumachella is most often mistaken for, or substituted by, Ammolite, Paua shell inlay, Labradorite or Ordinary fossiliferous limestone.
The separation is rarely a matter of opinion: refractive index 1.486-1.658 and specific gravity 2.60-2.80 settle most of it in a minute, and magnification settles the rest.
What lumachella is used for
Demand for lumachella comes from mineral collecting, decorative objects, architecture and interiors and jewellery, which is why one price per carat never covers it.
We quote each application in the unit that trade actually buys in, by the specimen, by the piece or by the square metre.
Durability and care
Lumachella is 3-4 on the Mohs scale, with calcite cleavage in grains cleavage.
Below about 5.5 a stone will be scratched by ordinary household dust, which is largely quartz. That does not make it unusable — it makes it a pendant, an earring or an object rather than a ring worn every day.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What lumachella costs
As a guide, lumachella trades around Collector and antique market; polished plaques $50-600.
That is a range, not a quote. Colour, size, clarity, cut and origin move the figure a long way inside it, and the only honest price is one given against a specific stone. Send us what you need and we will price it.
Questions
Is lumachella treated, and how?
Polished and waxed. Historically a prized inlay and snuff-box material in 18th and 19th century Europe; current supply is very limited and most pieces on the market are antique. Occasionally confused with ammolite, which is a much thicker and more intensely coloured nacre. Not CITES.
Where does lumachella come from?
Bleiberg and Hallstatt, Carinthia and Salzkammergut, Austria - the classic Triassic fire marble, Bastenaken, Belgium (historic) and Spain and Italy (related shell marbles). Origin affects price, so we name the locality rather than the country on every quote.
Is lumachella hard enough to wear every day?
Not really. At 3-4 on the Mohs scale it is softer than the quartz dust in ordinary household dirt, so it scratches with wear. It suits pendants, earrings and objects better than a daily ring.
How much does lumachella cost?
Indicatively Collector and antique market; polished plaques $50-600. Colour, size, clarity and origin move the price a long way within that, so treat it as a range and ask for a quote against a specific stone.
What is lumachella confused with?
Most often Ammolite, Paua shell inlay, Labradorite and Ordinary fossiliferous limestone. A refractive index of 1.486-1.658 and a specific gravity near 2.60-2.80 separate it quickly.
What is lumachella used for besides jewellery?
mineral collecting, decorative objects and architecture and interiors. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for lumachella?
Tell us the size, the quality and what it is for. We source it, photograph it and quote it — with the locality named.
Ask about lumachella