Just note that the correct form is "מִכְֿחוֹל" = Mihkhol (rafe).
Most people say Mik'khol, though
why is it written like blue
Because originally מִכְחוֹל was a brush used to apply blue eyeshadow.
Ha'mik'chol¹ ha'kachol shavur.
¹ On pealim.com as michchol. On Wiktionary.org as michekol. But other sites (including teachmehebrew.com) have it as I wrote it.