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THE PLANETARY GEMOLOGISTS DICTIONARY
ADULARESCENCE: An optical phenomenon applied to orthoclase or adulria feldspar that exhibits a floating, billowy, white or bluish light effect.
AGGREGATE: Crystalline aggregate made up of many particles, each of an individual crystal too small to be seen by the unaided eye.
ANTAR-DASHA: Minor planetary period.
ANUKUL: Favorable (Anukula-vad is belief that jyotish gems act same as their ruling planet, therefore gems should only be used for anukul or favourable planetary positions)
BIREFRINGENCE: The strength of double refraction measured by taking the difference between the high and low refractive indices of a doubly refractive gemstone.
CHANDRA-RASI: Moon sign.
CRYSTAL SYSTEM: One of the six groups of crystal patterns in which minerals and other crystalline solids occur. They are : cubic, tetragonal, hexagonal, orthorhombic, monoclinic and triclinic.
CUBIC: Highly symmetrical crystal system with three equal crystallographic axes at right angles.
DICHROISM: The property of doubly refractive colored gemstones of transmitting two different colors in two different directions caused by their unequal absorption of the two portions of a doubly refracted beam of light.
DISPERSION: The property of a transparent gemstone to separate white light into its component colors.
DOUBLE REFRACTION: The property of separating a single ray of light into two.
FLUORESCENCE: The emission of visible light by a gem when exposed to ultra-violet or X-radiation.
GAURA-PAKSHA: The bright fortnight.
HEXAGONAL: A crystal system having three equal axes at 60 degrees and a fourth axes perpendicular to the other three and unequal in length.
INCLUSION: Any internal foreign body or imperfection in a gem.
JANMA-PATRIKA: Sidereal horoscope.
JYOTISH: Vedic sidereal astrology.
JYOTISH-ACARYA: A master-teacher of Vedic sidereal astrology.
KAVACHA: A shield, amulet or talisman.
KETU: The Moon's descending (South) node.
KRISHNA-PAKSHA: The dark fortnight.
KRURA-GRAHA: A harmful planet.
LAGNA: Rising sign.
MAHA-DASHA: Major planetary period.
MANI: Gem or jewel.
MANTRA: A combination of transcendental (Sanskrit) sound vibrations with the power to deliver the mind from material limitations.
MATRIX: The rock in which a mineral is contained.
MOHS SCALE: The most commonly used scale of relative hardness of minerals with numbers from one to ten assigned to ten minerals of increasing hardness from talc to diamond.
MONOCLINIC: A crystal system with two axes unequal in length at right angles to one another and a third axes of unequal length which is not at right angles to the plane of the other two.
NACRE: Pearl substance.
NAKSATRA: Moon constellation (There are 27 constellations).
NAVA-RATNA: The Nine Gems.
OPTIC CHARACTER: The nature of a gem as either uniaxial (singly refractive) or biaxial (doubly refractive).
ORIENT: The iridescent luster of a pearl.
ORTHORHOMBIC: A crystal system with three axes of unequal length, each perpendicular to the plane of the other two axes.
PANCHA-RATNA: The Five Gems.
PLEOCHROISM: The property of most doubly refractive colored gemstones of exhibiting either two or more different colors when observed through a dichroscope in transmitted light.
PRATIKUL: Unfavorable (Pratikula-vad is belief that jyotish gems act OPPOSITE of ttheir ruling planet, therefore gems should only be used for pratikul or unfavourable planetary positions)
RAHU: The Moon's ascending (North) node.
RASI: Zodiac sign.
RATNA: Gem or jewel.
REFRACTIVE INDEX: A measure of the amount a light ray is bent as it enters or leaves a gemstone.
SAPTA-RATNA: The Seven Gems.
SHUKLA-PAKSHA: The bright fortnight.
SUBHA-GRAHA: A helpful planet.
SIDEREAL: Constellational astrology.
SINGLE REFRACTION: When a light ray enters either an isometric or amorphous gem substance, it remains intact and is refracted in the normal manner as a singly ray.
SPECIFIC GRAVITY: The ratio of the weight of a gemstone to that of an equal volume of water at 4 degrees centigrade.
STOTRAM: A Sanskrit prayer and invocation.
TETRAGONAL: A crystal system with two axes equal in length and at right angles with a third axes at right angles to the first two.
TRICHROISM: The property of most doubly refractive, colored gemstones belonging to the orthorhombic, monoclinic, and triclinic crystal systems, of transmitting three different colors in three different directions when observed through a dichroscope in transmitted light.
TRICLINIC: The least symmetrical crystal system with three axes, no two of which are of equal length and no two of which are perpendicular to one another.
TRI-RATNA: The Three Gems.
Ref. ©1995 Ancient Astrological Gemstones & Talismans
The Sanskrit name for the PGA was composed by HONORARY PATRON Prof. Dr. Satya Vrat Shastri, Padma Sri