What's the plural form of crystall? Here's the word you're looking for.
Answer
The noun crystall can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be crystall.
However, in more specific contexts, the plural form can also be crystalls e.g. in reference to various types of crystalls
or a collection of crystalls.
Examples
And from her cleare and crystall eyes The teares gusht out apace, Which like the silver-pearled dewe Ranne downe her comely face.
Nay, a Crystall glasse will not show a man his face, except it be steeled, except it be darkned on the backside.
