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