What's the plural form of arragonite? Here's the word you're looking for.
Answer
The noun arragonite can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be arragonite.
However, in more specific contexts, the plural form can also be arragonites e.g. in reference to various types of arragonites
or a collection of arragonites.
Examples
In the cavities of such mixed rocks we often find calcedony, and crystals of mesotype, stilbite, and arragonite.