Gemology
Introduction
Gemology, also known as gemmology, is the science dealing with natural and artificial gemstone materials. It is a geoscience and a branch of mineralogy, but also has many aspects of chemistry, physics, and geology.
History
The study of gemstones began in ancient times. The Greeks, for example, identified different types of gems and attributed various properties to them. The science of gemology, however, did not begin to develop until the late 19th and early 20th centuries, with the establishment of gemological institutes and laboratories.
Gemstone Formation
Gemstones are formed under various conditions in the earth's crust. The most common process involves the crystallization of minerals from magma. Other gemstones are formed through metamorphism, a process where rocks are transformed by heat and pressure. Some gemstones, like pearls and amber, are organic and are formed by living organisms.
Gemstone Properties
Gemstones have various properties that make them valuable and desirable. These include color, clarity, cut, and carat weight, collectively known as the "Four Cs". Other important properties include hardness, specific gravity, refractive index, and dispersion.
Gemstone Identification
Identifying gemstones involves determining their physical and optical properties. This can be done through visual inspection, but more often involves the use of specialized tools and equipment, such as a loupe, a dichroscope, a refractometer, and a spectroscope.
Gemstone Treatments and Enhancements
Many gemstones are treated or enhanced to improve their appearance or durability. Common treatments include heating, irradiation, dyeing, and oiling. These treatments can affect the value of a gemstone, and are therefore important to identify.
Gemstone Grading
Gemstones are graded based on their color, clarity, cut, and carat weight. The grading process involves the use of standardized systems and scales, and requires a high level of expertise.
Gemstone Mining and Trade
Gemstones are mined in many parts of the world, with different regions known for producing specific types of gems. The trade of gemstones is a global industry, with major trading centers in cities like Antwerp, New York, and Hong Kong.
Ethical and Environmental Considerations
The mining and trade of gemstones have significant ethical and environmental implications. Issues include labor rights, conflict funding, and environmental degradation. There are initiatives and certifications aimed at promoting ethical and sustainable practices in the gemstone industry.
Careers in Gemology
There are many career opportunities in the field of gemology, including gemologist, appraiser, jewelry designer, and gemstone dealer. Many of these careers require specialized training and certification.