The internet suggest both spellings are valid.

( Monty Boyce, My cheese game is strong, Tue 8 Jan 2013, 13:31, 2 replies, latest was 12 years ago)

you know how dim people make themselves sound when they go on at length
on subjects where they have done all their research on wikipedia?

hmmm??
( rachelswipe with a fork, Tue 8 Jan 2013, 13:33, Reply)

Does off topic count as a formal context?
The standard spelling is minuscule rather than miniscule. The latter form is a very common one (accounting for almost half of citations for the term in the Oxford English Corpus), and has been recorded since the late 19th century. It arose by analogy with other words beginning with mini-, where the meaning is similarly ‘very small’. It is now so widely used that it can be considered as an acceptable variant, although it should be avoided in formal contexts.
( tangledupinblue hairy badge with moving eyes, Tue 8 Jan 2013, 13:33, Reply)

I'm going to say 'no', here.

( Monty Boyce, My cheese game is strong, Tue 8 Jan 2013, 13:34, Reply)

i think
you just called monty "very common". gauntlets at dawn.
( rachelswipe with a fork, Tue 8 Jan 2013, 13:35, Reply)

My honour is at stake here.

( Monty Boyce, My cheese game is strong, Tue 8 Jan 2013, 13:35, Reply)