What's the plural form of pyrosmalite? Here's the word you're looking for.
Answer
The noun pyrosmalite can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be pyrosmalite.
However, in more specific contexts, the plural form can also be pyrosmalites e.g. in reference to various types of pyrosmalites
or a collection of pyrosmalites.
