About the Queen and diamonds

One of my alien friends asked me who are these women who are shown in coins, stamps and in everywhere.

First I had to explain him she is only one woman.

Me: Someone took photos of her in different ages and put them here and there.
My alien friend: Why?
Me: People do weird things all the time. I just tell the fact.
My alien friend: Oh, maybe she is someone very relevant and superior. Maybe a divinity?
Me: Sure she is for many!

My alien friend took his DNA analyzer device and checked a sample of Queen's DNA.

My alien friend: Looks nothing valuable. The result shows a damaged DNA from an old human, lower quality than average and not recommended to use for cloning.
Me: That's not the value. Please check up, in her head.
My alien friend: You mean her brain? Does she has privileged brain?
Me: No, no... Her crown! It's make of gold and full of diamonds. Diamonds!
My alien friend: But her crown is not she. Did she make it?
Me: Actually no... See, diamonds!

My alien friend used another device and checked one of the diamonds.

My alien friend: Well, it's just a normal Carbon structure, quite usual.
Me: Yes... it is.
My alien friend: But then, why...?
Me: Hey, see! The stamps are so colorful and nice!!!