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