 The gem analysis points out the recurring themes of precious gems and the use of gemology and mineralogy to make points.The names reflecting peridot and sapphire are purely for effect, but serpentine is unusual as it is dark, not a gemstone or particularly valued, and it is associated with serpents.The connection may be to prime readers for the amphibian transformation, as to children both frogs and snakes are considered slimy, disgusting 'creepy crawlies'.