Starstones are special stones that always remember where they last were. They usually flash green, but some rarer ones are blue. A notable, blue-flashing Starstone was owned by Lady Gisela and used in a hairpin to travel to Nightfall; another similar one traveled to her bedroom, which was found at Cyrah's stall. They were both made by Cyrah Endal.
“The silver-white stone was smooth and oval, but when the light hit it, thin veins of blue shot through in an asterisk pattern”