A lot of royal tiaras and necklaces are first Rose cut. Which one ?

During the 19th Century Old Mine Cut diamonds and later old european cut diamands (round in Shape).

What is their value yet ?

Before and after WW1 we have the modern brillant cut on 57 faces. (which makes the diamond smaller)

They are a lot of of tiaras from the past , such as those from the British Nobilities . Were they so expensive they are now ?

When I see on You Tube all these tiaras gliterring I don't know which cut and quality have these diamonds .

It is a question that is important to me. Thank you for corecting and helping . Myself I have to thank a Friend who helped me for the english words. MO