Is there a type of diamond ring a son would give his mother?

I have to admit, I'mma momma's boy in the sense I love my mother to death. My father was a deadbeat but I still xbox 360 under the tree or whatever new thing that came out on christmas due to my mothers unconditional love for me, and her mindset of spoiling her only child. Some people look down upon that and that's fine but my mother my entire life always said I want a 1 caret diamond ring. Her wedding band was only 1/4kt, my father would NEVER spend that kind of money on a ring. Well I've worked my tail off and have come into money where I can afford the diamond ring she always wanted. The problem is I always see diamond rings for your girlfriend and future wife. I'm only twenty, and my girlfriend and I won't be getting married anytime soon. Is there anytime of diamond ring that a son would give to a mother? I don't think there is. So the question is, is there any type of diamond ring 1 kt that a son would give his mother?