Stibnite (antimonite) from Tuscany already enjoys an excellent reputation among collectors, but specimens from the Capalbio mine (often associated with the Pozza del Lino locality) appear on the market extremely rarely. Tuscany is world-renowned for its complex, hydrothermal antimony and mercury mineralizations, but most of the well-known display specimens come from classic mines like Le Cetine or Pereta. Capalbio material, by comparison, represents an absolute mineralogical niche.
What is particularly fascinating about your 7 cm specimen is its paragenesis and preparation. The steel-gray, metallic-lustrous stibnite needles were originally completely embedded in gypsum (selinite). Gypsum and stibnite form here in shallow, low-temperature hydrothermal systems. Only through the careful chemical etching of the surrounding gypsum matrix with a weak acid (or painstaking mechanical removal, as gypsum is very soft) was this delicate, needle-like to radiating network exposed without damaging the fragile crystals.
The trace of metastibnite you mentioned—an amorphous, usually reddish-brown modification of antimony trisulfide—is a wonderful indicator of the dynamic conditions of its formation. It often forms under metastable conditions at very low temperatures, either directly with the stibnite or as a very thin coating through subsequent alteration processes. The close-up photographs beautifully show how the needle-like crystals exhibit the characteristic rough texture and typical galena, embedded in the light-colored, crystalline matrix remnants. An aesthetically pleasing, scientifically fascinating, and above all, historically valuable piece of Tuscan mining history.
Such a specimen is a true rarity for any advanced regional or specialist collection of sulfide minerals.
Size: 7.0 x 5.5 x 4.5 cm
Locality: Pozza del Lino quarry, Borgo Carige, Capalbio, Grosseto Province, Tuscany, Italy
