Might ancient mid-latitude Mar's ice be covalently bonded? Would 1-2 billion year old ice have much greater density then, compared to earth ice? So drilling into Mars' ice, compared to drilling into earth ice, and measure relative difference in voltage/ampere as a proxy for relative density. Could one bring back a cube of Mars ice, without melting? Also wouldn't such guessed at Mars ice sink in water? Would it super cool your drink?