Diamonds are a very good store of wealth. They have very high value per weight. They are easily hidden. They do not corrode.
But they don't serve well as money for two reasons
1. Beauty is in the eye of the beholder. There is no standard for exact valuation. Gold in ounces is the same stuff everywhere at all times.
2. They are not divisible.
These two reasons make them illiquid for trading; a most necessary component for money.
That said, diamonds are always super precious in perilous times like these. Very wealthy people have many times preserved their fortunes with them.
P.