This content was first published on IGR – Italian Gemological Review no. 7 in 2019. The information provided here is therefore current as of the original publication date.
Rhodonite is a manganiferous pyroxene with hardness 5.5-6.5, very rare as crystals but quite common as pink or red colored masses.
In Italy there are two important deposits of manganese where good gem quality rhodonite can be found, Gambatesa, in Graveglia Valley, province of Genoa, and Praborna in Aosta Valley (Figure 97).
On oceans’ seabed where magmatic activity takes place near the ridge, deposits of manganese are common. In fact this element is ejected in large quantities by the underwater fumaroles named “black smokes”.
When these deposits are metamorphosed into alpine bending, originally present manganese as incoherent black mud originates the crystallization of a great quantity of manganese minerals, mostly vividly pink and red colored.
Rhodonite of Gambatesa and Praborna are of very good quality and color. Crystals are generally too small for faceting, but the massive variety is as good as the most common ones available in the market such as those from Australia, California and Sweden. From the Italian material it is possible to produce beads, cabochons and small carvings.
Rhodonite can be found also in Piedmont, in Alagna, in the province of Vercelli, and in Chiaves, in the province of Turin (Figure 98).
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Curated by the qualified group of expert of the section Gems of Italy, published on IGR – Italian Gemological Review #7, Summer 2019.
