first post! any idioms related to "100% cotton (全部が綿100％)"?

hello! i'm a rookie translator, and i got stuck translating this light novel-format media i'm reading. i thought i should go to a fitting subreddit. 失礼します！

there's this sentence the side character says:

「え、えっと。真里亞ちゃんみたいに……全部が綿100％ってことは、ないかな……」

"e, etto. Maria-chan mitai ni... zenbu ga men (wata?) 100% tte koto wa, nai kana..."

the context might be too grey area to share here and i don't want to break rules. let's just say Maria-chan was out shopping with two friends and realised she's "not so normal" for not having a certain thing unlike her friends. then one of the latter said the sentence above.

currently i'm translating it to:

"u-- um. someone (something?) 100% cotton like Maria-chan... might not exist..."

any idioms related to "綿100%"? i thought it might be an idiom since the context didn't really make it make sense. but if it's not, then maybe it just refers to the certain thing Maria-chan doesn't have. i looked up what it could possibly mean but Google just showed actual 100% cotton shirt catalogues. i just wanna leave no stone unturned; i learnt new idioms while translating this thing, so i thought i'd ask!

thanks in advance!