The other palm imprints were those made by other Harmonisers in the Royal Clan. It was their very first release of a Palm Projection. The rock pillar she had unleashed her Palm Projection was one used by the Harmonisers who had the highest affinity to the water element.
So, all the Palm Projections created a sharp impression on the rock pillar without a single crack. The rock pillar on which Ki'Nua had slammed her Palm Projection on was a heirloom of her family for generations.
Those in her family tree had unleashed their first water-based Palm Projection on it. There were three other rock pillars positioned nearby. The impressions made by the water-based Palm Projections were sharp, not even sporting a single crack due to the impact.
This showed the water's fluid properties.
The impressions made by the metal-based Palm Projection too was sharp, but the area of impact was covered by cracks, displaying the properties of metal to store and transmit shock.