Or, well, something like Ice-9. At least, so says New Scientist:
Layers of ice of few nanometres thick can remain frozen at human body temperature when grown on top of diamond sheets with a surface layer of sodium, detailed calculations suggest.
The icy coatings could help make diamond-toughened medical implants more biocompatible, according to the Harvard University team who carried out the work.
…
“We think our discovery will prove crucial for making scratch-resistant diamond coatings for medical implants – such as prosthetic joints – more bio-friendly,” Wissner-Gross told New Scientist. “The warm ice layer stabilised by the diamond could protect tissue from abrasion, as well as prevent blood clotting on the diamond’s surface,” he adds.