I cannot believe how just plain mean my Aunt is! (long)

Just a vent because my stomach is in a huge knot and I have been crying for a hours.
My Dad's sister is so awful. When my Nanny died she left a few pieces of jewerly- nothing Harry Winston or anything but pieces that meant a lot to her. My Nanny was THE most important person in my life. Losing her 4 years ago is still heartbreaking to me and I miss her every single day.One in particular was diamond cross that she wore almost everyday of her life since the day my grandfather gave it to her when I was a small child. Anyway long story short she cleaned out my Nanny's house when she died and took everything with her, except for a few household things that she 'let' my sister and I have. These household items, while nice, really have very little emotional tie-in to my Nanny. She never used her silver so while I love it, I don't say 'I remember my Nanny' when I see it.
Anyway I had to ask my Aunt for the cross to wear on my wedding day. I KNOW that if my Nanny were alive it would have meant the World to her that I wear it. My Aunt gave it to me to wear. My Dad told me that he wants me to keep it and that my Nanny always wanted me to have it but my Aunt is a psycho and grabbed it quick. Now that I have it my Aunt told me she wants it back and I told her how much it means to me to have it and that I really want to keep it and use it for my some-day children's christenings and it makes me feel so close to nanny when I wear it. She flipped out and told me that SHE is the daughter NOT me and that I will have he__ to pay if I even think of keeping it and she was screaming louder than my own father has ever even screamed. So I hung up the phone and called me Dad. He said he doesn't care what his sister wants and I am keeping the necklace that my Nanny always wanted me to have and that is that. So now WWIII has started in my family and I feel awful but I am more upset that my own Aunt could say horrible things to me and threaten me. I KNOW my Aunt just wants to give all of my Nanny's stuff to her son someday, even though he is NOT even in a relationship with anyone and that person will not even have known my Nanny. She is such a miserable person.