Silvering the backs of stones

 Can the back of a stone, perhaps moonstone or even thin obsidian be
silvered like the glass used in mirrors? 

G’day; Yes! there is a chemical method, but it needs some expertise
and in the wrong hands could be hazardous. Metals like aluminium,
gold, silver, etc can also be evaporated on to a stone in a vacuum -
but the setup is VERY expensive. Cheers,

    /\      John Burgess
   / /
  / /      Johnb@ts.co.nz    
 / /__|\
(_______)