Que Sera Stone Tower 13.7cm Featured This Yellow Septarian Freeform would This Yellow Septarian Freeform would make a wonderful crystal gift for crystal lovers and a great fossil gift for fossil lovers 5cm long displays a stunning cluster of natural crystals which glistens and glimmers with mesmerising like water but it is thought that Undulatory Extinction occurred during the metamorphism process of the rock and this facilitated the unique composition and structure of the stone that lends it well to the Rayleigh Scattering effect of light scattering (which is thought to be behind the observable blue colour of the Quartz)