Percolating mineral solutions have filled areas in the rock (illustrated below) – water rich in minerals (possibly manganese and iron) has moved along a bedding plane between layers of sandstone (Beaufort Group rocks of the Karoo Supergroup), depositing dendritic crystals.
The specimen was brought to the museum by Brendon Stolze from Nahoon. He found it in the family garden at home. Thinking it might be a plant fossil this pseudo-fossil was identified as a dendrite by the natural history department.
Albany Museum colleague and palaeo-botanist, Dr Rose Previc, is thanked for confirming the identification.