Is there a name for this type of ice crystal?
This is needle ice which forms when moist soil freezes, for example during a cold night. Freezing starts at the ground surface and as ice is formed moisture gradients develop which draws water to the freezing front and growth continues. Ideal conditions may be a sub-freezing night after a rainy day or a sub-freezing night after a day of snow melt.

According to the National Snow and Ice Data Center (NSIDC) site needle ice be up to 40 cm in length. Since the favourable conditions are not unique to soils, although most often encountered in soils, needle ice can develop from freezing of, for example, vegetation