Gemology

History and Background of Gemology

• Rudimentary education in gemology began in the 19th century.
• The Gemmological Association of Great Britain (Gem-A) was established in 1908.
• The first US graduate of Gem-A's diploma course was Robert Shipley.
• Gemological Institute of America (GIA) and American Gem Society were established by Robert Shipley.
• Gemological laboratories serving the jewelry trade were established in London in 1925.
• Expert judgment from a neutral laboratory is often difficult to obtain.
• Gemologists and gemstone buyers use mobile laboratories for on-site analysis.
• Gemstones are categorized based on crystal structure, specific gravity, refractive index, and optical properties.
• Gemological microscopic study is used to determine if a gem is synthetic or natural.
• Spectroscopic analysis allows gemologists to identify the origin of a gemstone.

Gemological Instruments

• Gemologists use tools such as a corrected 10× loupe, microscope, refractometer, polarizing filter, and magnifying eyepiece.
• Other instruments include a dichroscope, spectroscope, penlight, tweezers, stone cloth, and color filter.
• Immersion cell and ultraviolet lamp are also used for gemstone identification.
• Gemologists may use a gemmological travel lab for convenience.
• These instruments allow for accurate tests to identify gemstones.

General Identification of Gems

• Gem identification is a process of elimination.
• Non-destructive optical testing is used to determine gemstone identity.
• Specific gravity is a useful property for distinguishing gemstones.
• No two gems are identical due to geological environment and structural imperfections.
• Chemical impurities and substitutions create individual gemstones.

Identification Methods

• Refractive index is measured using a refractometer or microscope.
• Specific gravity is determined by comparing the weight of a gem in air and in water.
• Spectroscopy analyzes selective absorption of light to identify the gems' color.
• Inclusions help determine if a gemstone is natural, synthetic, or treated.
• Flaws and striations can indicate whether a gemstone is lab-created or natural.

Introduction to Gemology and Importance

• Gemology is the study of gemstones.
• It involves examining the physical and chemical properties of gemstones.
• Gemologists use various tools and techniques to identify and grade gemstones.
• Gemology is important in the jewelry industry for determining the quality and value of gemstones.
• Gemology can also involve the study of gemstone history, folklore, and cultural significance.
• Gemology plays a crucial role in the gemstone industry by ensuring transparency and authenticity.
• Gemologists help consumers make informed decisions when purchasing gemstones.
• The knowledge and expertise of gemologists contribute to the overall quality and value of gemstones.
• Gemology is essential for gemstone appraisals and certifications.
• Gemology also contributes to the preservation and understanding of gemstone heritage.

Gemology Data Sources