Roughly 4 - 4.5 cm at the longest point of the crystal and approximately 3.5 - 3.5 cm in width. (May vary due to the asymmetrical shape of each palm stone). 

Colouring of palm stones are mainly are vibrant red that can also contain flecks of black.
 
Chakra - Root
Energy - Absorbs
Grounding, Manifestation, Stability, Balances excessive energy