The name Sapphire Stone (Astrology Semi precious Gems) used to be applied to various stones. In antiquity and as late as the Middle Ages, the name sapphire was understood to mean what is today described as lapis lazuli. Around 1800 it was recognized that sapphire and ru are gly the blue variety was called sap-phire, and corundums of other colors (with the exception of red) were given spe-cial, misleading names, such as “Oriental peridot” for the green variety and “Ori-ental topaz” for the yellow type.
Today corundums of gemstone quality of all colors except red are called sap-phire. Red varieties are called rubies. The various colors of sapphire are qualified by description, e.g., green sapphire or yellow sapphire. Colorless sapphire is called leuko-sapphire (Greek—white), pinkish orange sapphire Padparadscha (Sinhalese for “Lotus Flower”).
There is no definite demarcation between ruby and “Pink Sapphire Stone – Astrology Semi precious Gems”. Light red, pink, or violet corundums are usually called sapphires, as in this way they have individual values in comparison with other colors. If they were grouped as rubies, they would be stones of inferior quality. The coloring agents in blue sapphire are iron and tita-nium; and in violet stones, vanadium. A small iron content results in yellow and green tones; chromium produces pink, iron, and vanadium orange tones. The most desired color is a pure cornflower-blue. In artificial incandescent light, some sap-phires can appear to be ink-colored or black-blue.
Through heat treatment at temperatures of about 3100-3300 degrees F (1700-1800 degrees C), some cloudy sapphires, nondistinct in color, can change to a bright blue permanent color.
Hardness is the same as ruby and also differs clearly in different directions (an important factor in cutting). There is no fluorescence characteristic for all sap-phires.
Inclusions rutile needles result in a silky shine; oriented, i.e., aligned, needics cause six-rayed star Vedic Sapphire Stone or Astrology Semi precious Gems .
Sapphire Stone Characteristics
Color: Blue in various tones, colorless, pink, orange, yellow, green, purple, black
Color of streak: White
Mohs’ hardness: 9
Irystal system: (Trigonal), doubly pointy, barrel-shaped, hexagonal pyramids, tabloid-shaped
Chemical composition: Al203 aluminum oxide
Transparency: transparent to opaque
Refractive index: 1.762-1.788
Double refraction: —0.008
Dispersion: 0.018 (0.011)
Pleochroism: Blue: definite; dark blue, green-blue
Yellow: weak; yellow, light yellow
Green: weak; green-yellow, yellow
Purple: definite; purple, light red
Absorption spectrum: Blue, Sri Lanka, 4711 460 455, 450, 379 Yellow, 471, 460 450 Brown, 471, 460-450
Fluorescence: Blue S.: none; Colorless S.: orange-yellow, violet