Phosphophyllite

Was TAing geology students in the field of NM, we saw wonderful geology settings and mineral deposits, some include Valles Caldera.

Here, is a very uncommon tetrahydrate phosphate mineral from the early Miocene Kari Kari caldera complex. Phosphophyllite from Potosi, Bolivia, are well known to collectors for their beauty, large size, and rare-gem potential. They were discovered in the mid-1950's from Cerro Rico de Potosi （CRP)and rapidly became one of the most popular, classic minerals for many collectors.

CRP is the world’s largest silver deposit and has been mined since 1544. It is also one of the many deposits carrying Ag and Sn which occur mainly within the Eastern Cordillera of Bolivia and collectively form the major part of the central Andean tin belt. It is mainly hydrothermal vein-hosted mineral deposit and these beautiful mint color crystals are found in the lower-temperature mineral assemblage consisting principally of sphalerite, galena, lead sulfosalt, and silver minerals. Perhaps represents the cooling of the main hydrothermal system.

I got lucky on finding this little treasure that two crystals with different styles within a toenail specimen. Matrix specimens are rarely found because the matrix is brittle and phosphophyllite itself has perfect cleavages and low hardness. The major crystal on the bottom is twinned and the other is a single crystal. You can see how gemmy they are in the close up photos.

3.2cm, Cerro de Potosí, PPotos, Tomás Frías Province, Potosí, Bolivia

Jingnan Zhang Coll & Photo