Abstract 2024
Rivista Mineralogica Italiana > Abstract Articoli
Abstract ITALIAN MINERALOGICAL MAGAZINE nr. 1-2024 | ||||||
TINZENITE THE FINDINGS FROM THE Mn ORE DEPOSITS OF EASTERN LIGURIA  | The Mn ore deposits of Eastern Lig- uria are well-known for several mineral species, in some cases occurring in aesthetic specimens. Among them, tinzenite forms classic specimens actively sought by mineral collectors. This mineral belongs to the axinite group, along with axinite-(Fe), axinite-(Mg), and axinite-(Mn). Its troubled definition and its relations with the other members of the axinite group are briefly reviewed. It is worth noting that tinzenite was misidentified as spessartine by Alberto Pelloux in 1919, four years earlier the first description from the Swiss locality of Tinzen, Grisons. Samples of tinzenite from Liguria were later used for the investigation of the crystal chemistry of this mineral that has been recently redefined with the ideal end-member formula Ca Mn Al [B Si O ](OH) . Tinzenite has been found in several ore deposits of the Graveglia Val- ley, i.e., those formerly exploited by the Gambatesa, Cassagna, Molinello, Statale/Scrava and Monte Bossea mines. Tinzenite occurs as veins hosted in braunite or cherts, in some cases characterized by cavities lined by lenticular crystals, showing colour ranging from salm- on-pink to yellow to orange. Associated minerals are calcite, caryopilite, chalcocite, clinochlore-pennantite, cuprite, gamagarite, ganophyllite, harmotome, hematite, kutnohorite, marcasite, piemontite, quartz, rhodochrosite, and sursassite. In this paper, the most significant findings of the last fifty years are summarized. In the upper part of the Molinello mine, during the 1970s, some nice findings were performed by local miners, who collected specimens where tinzenite is associated with quartz and sursassite. A specimen representative of these findings is currently kept in the Natural History Museum “Giacomo Doria” in Genoa. In the second half of the 1980s, the open-pit works at the Cassagna mine allowed the find ing of a vein of tinzenite, up to 10 cm in thickness, with some cavities lined with tinzenite and quartz crystals. Unusual specimens with a salmon-pink colour were collected from this locality. At the end of 1989, a couple of well-crystallized specimens were extracted from a tinzenite vein hosted in the braunite ore from the Monte Bossea mine. However, the most important finding was performed in 2002 at the Molinello mine. Several beautiful specimens were collected, showing aesthetic aggregates of crystals of tinzenite associated with quartz and sursassite. At this same locality, new findings have been performed recently. Tinzenite is reported in nice specimens from other minor ore deposits of Eastern Liguria (e.g.,Monte Alpe and Colli di Tavarone). | |||||
NATIVE COPPER OF EASTERN LIGURIA  | ||||||
AXINITE-(Mn) FROM MONTE PÙ (CASTIGLIONE CHIAVARESE, GENOA). A CLASSIC OCCURRENCE FROM EASTERN LIGURIA  | The small Mn ore deposit of Monte Pù (Castiglione Chiavarese, Genoa) has been known since the 1960s for the occurrence of nice specimens of axinite-(Mn), showing aggregates of brown-greenish crystals, up to 1 cm in size, in veins hosted in manganiferous cherts. For several years some Ligurian mineral amateurs collected specimens of axinite-(Mn) from the old dumps of the Monte Pù mine, whereas few specimens of this species, associated with epidote, were collected in an outcrop of cherts along the Frascarese stream, not far from the mine. During the 1990s, mineral collecting in the old dumps was forbidden. In Spring 2021, the ban was nlonger present and a new exploration of the mining area of Monte Pù allowed the identification of some veins hosted in cherts and the finding of the adit of a short tunnel where it was possible to collect nice specimens of axinite-(Mn), associated with quartz, calcite, and, sometimes, hematite. Few specimens of “axinite” from Monte Pù revealead a nice red fluorescence under long-wave UV light. | |||||
Abstract ITALIAN MINERALOGICAL MAGAZINE nr. 2-2024 | ||||||
Abstract ITALIAN MINERALOGICAL MAGAZINE nr. 3-2024 | ||||||
Abstract ITALIAN MINERALOGICAL MAGAZINE nr. 4-2024 | ||||||