sweet 16

Heyy guyss. so my mum designed for me this necklace when she was still pregnant (in me!!) and gave it for my sweet sixteen. I was literally speechless and i teared up , its really sweet and touching. Im really willing to give it to my future daughter ( if i didn't get any, my daughter in law!!) and keep it a memory of my mother generation to another. So here it is , just a simple pink heart. it's been a year since (i turned 17 in december) but today mum and i where discussing the type of this precious stone , she promised me its a precious stone ( not as if it matters anyway ,precious or not it's previous ,i love it ) but she forgot it's name. Does anyone know what could it be??

PS: when sun hits it disperses mini rainbows like a discoball 😍