1.   Not, to be sure, the malign, tentacled geniuses invented by H. G. Wells, but things a bit closer to terrestrial bacteria.

2.   So the Martian crystals are similar to those found in terrestrial bacteria.

3.   Such minerals are not necessarily a sign of life, but in some cases they have been produced by terrestrial bacteria.

4.   Terrestrial bacteria commonly produce such thin films.

5.   The smallest certified terrestrial bacteria are twice that size.