can be used with an article as follows:
1- Un bolso mío es rojo. (A bag of mine is red)
2- El bolso mío es rojo. (The bag that is mine is red) (This is more emphatic than "Mi bolso es rojo")
3- Ese bolso rojo es el mío. (That bag over there is the one that belongs to me)
Without an article, the mentioned ...