The respective symbolic meanings of white and black are illustrated in the designations “white magic” and “black magic,” the latter denoting conjurations or spells in which the aid of the powers of darkness, of the Devil and his demons, was sought by the sorcerer, while “white magic” was to be performed by harmless and innocent means, sometimes even by religious rites. In this way it sometimes so closely approached the domain of religious miracle, that it becomes difficult to distinguish between these two conceptions of supernatural action in the material world. Quartz of a different type with needle-like inclusions is called “Thetis’s hair stone.” This is a transparent or translucent quartz, but so completely filled with acicular crystals of green actinolite, or occasionally altered actinolite of a yellow-brown or brown color, as to appear almost opaque; seals and charms have been made to a small extent of this variety. Of other inclusions in quartz we may note those of a very brilliant stibnite projecting in all directions, some of the intruded crystals being very curiously bent. Exceedingly beautiful gems have been cut from this material.[48] When this quartz is cut en cabochon across the ravalette inclusions, a cat’s-eye effect is produced. The yellow quartz cat’s-eye of Ceylon and the green of Haff, Bavaria, are of this type. So densely set were the green actinolite inclusions in the case of a specimen found at Gibsonville, North Carolina, that it was believed by the finder to be an emerald. An extremely beautiful effect in quartz is produced by enclosed, acicular crystals, or hair-like particles of some other mineral, such as rutile, for instance, and sometimes even of gold. To specimens of this latter type may be referred the Greek name “chrysothrix,” used in the Orphic poem “Lithica” and signifying literally “golden hair”; of this the verses tell us there were two varieties, that which may be identified with quartz, having a resemblance to “crystal,” while the other, said to have the appearance of chrysoberyl, may have been a yellower variety. To the quartz traversed by filaments of rutile, or the red oxide of titanium, has been given the taking name of “Venus’s hair stone”; a pretty French name is _Flèches d’Amour_ or “Cupid’s Arrows.”[49]