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