Snowflakes, as were imaged on HR-SEM at cryogenic conditions (-145 deg C).
These are found to be contamination of original sample surface
Courtesy of Olga Kleinerman
Instrument used: XL SEM Family
Horizontal Field Width: 88644.5 micron
Vacuum: 3E-6 mbar
Voltage: 1 keV
Working Distance: 2.5 mm