Chalcophile. What does it mean?
Mineral Matters #389
I have recently saw the term chalcophile used in a geological paper whilst discussing bismuth minerals. Not knowing what it meant, I decided to try and find out.
In geology, "chalcophile" refers to a specific classification for elements based on their affinity with sulphur during the early stages of planetary formation or during magmatic processes.
The word "chalcophile" comes from the Greek words "χαλκός" (“chalkos”, meaning copper) and "φίλος" (“philos” meaning loving). While the literal translation suggests a love for copper, in geochemical terms, it signifies a strong affinity for sulphur, which is a component of sulphide minerals.
Chalcophile elements have a greater tendency to bond with sulphur to form sulphide minerals rather than bonding with oxygen to form silicate minerals. This is because the chemical behaviour of these elements allows them to form stronger and more stable bonds with sulphur compared to oxygen under the high-temperature and pressure conditions that existed during early Earth's formation or during magma differentiation.
Some prominent chalcophile elements include bismuth, copper, lead, zinc, nickel, molybdenum, and selenium.
In essence, chalcophile elements are those that have a strong preference for bonding with sulphur and tend to concentrate in sulphide minerals. The concept of chalcophile elements, along with the concept of siderophile (iron-loving) and lithophile (rock-loving) elements, provides a framework for understanding the geochemical behaviour of elements in geological processes.
Below: Bismuth, Stormont Mine, Moina, Tasmania. Width of view 3.5mm.
It is very annoying that it's not "sulphophile" or some similar spelling.
I've been advised that molybdenum is not, most definitely NOT, chalcophile. Mo is generally considered to be siderophile with strong lithophile tendencies (sometimes considered the other way round) but in no sense is it chalcophile. Nickel is generally considered siderophile with strong chalcophile tendencies. These terms have a lot more to do with how an element partitions in a melt than whether or not it forms sulphides. Gold, for example, is siderophile despite being most commonly recovered either from sulphide ore bodies or from quartz structures. (Thanks Roger)