HELIOTROPE, GEMSTONE, in mineralogy, is the mineral commonly called " bloodstone " (q.v.), and sometimes termed girasol a name applied also to fire-opal. The name, like those of many ancient names of minerals, seems to have had a fanciful origin. According to Pliny the stone was so called because when thrown into the water it turned the sun's light falling upon it into a reflection like that of blood.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)