What are the physical properties of non-metals?

Some non-metals exist in solid state while some are in gaseous state. However, bromine is the non-metal, which is an exception as it is found in liquid state. Non-metals except iodine, which is shiny do not have lustre. Non-metals are not hard. However, the allotrope diamond is the hardest natural substance. Meanwhile, the melting and boiling points are low for non-metals. They are also bad conductors of electricity and heat. But, Graphite, an allotrope of carbon, an exception is a good conductor of electricity.