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