Question: Is their a crystal more valuable than a diamond?

Serena Corr answered on 26 Jun 2013:

Diamonds are very expensive – which I guess makes them valuable. In terms of how expensive it is to make something though, there is an element that has a bigger price tag. The element Californium costs a whopping $27 million dollars per gram to make! It was first made at the University of California, Berkeley in 1950 and so far around 8 grams of it has been prepared.