Properties of giant covalent structures
Substances with giant covalent structures are insoluble
Diamond does not react with or dissolve in water.
Put a diamond in a glass of water and there will be no reaction.
Giant covalent structures have very high melting points
Diamonds have very high melting points.
If you use a Bunsen burner to heat a diamond it will have no effect.
Giant covalent structures don’t conduct electricity
Substances with giant covalent structures don’t usually conduct electricity (graphite is the exception).
Diamonds don’t conduct electricity.