Detail Slab
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Onice Vulcano

The close-up view of each stone type shows a relatively true image of the crystalline structure and the colouring. This is suitable for grained slabs to a limited extend only. In regard to the colour matching, please take an original sample of the stone from your furniture store as a basis.


The base structure of this lightly transparent rock consists of the mineral aragonite. This mineral, chemically identical with the lime spar, can be recognised by its needle and stem-like crystals (especially in a rough fracture surface). The warm, yellow-orange shade is achieved by varying concentrations of iron oxides limonite and hematite. 


Rock of this kind is generated at outlets of thermal wells which have lime-containing water. The lime deposits at the bottom and forms after some time the so called lime sinter terraces, which are also known from Pamukkale (West-Turkey). In case of sufficient thickness the rock, also named "Onyx?, is quarried. As the deposits are mostly relatively small, the stone is rare and expensive. Depending on the deposited metal oxides, blue, green, honey-yellow, as well as types with coloured bands are available in trade.

Hardness Soft Stone
Structure Type Slab with Irregular Pattern
Synonyms Onice Rosso Orientale
Group Sediment rock
Petrographic Assignment Lime sinter (Onyx)
Age Some hundred thousand years (Quaternary)
Colouring Minerals Aragonite, coloured by limonite (yellow) or hematite (red)
Average Hardness 3 (according to Mohs's hardness scale 1-10)
Deposit Turkey, Province Balikesir