Classification and Characteristics of Precious Gems
In the realm of gemology, the classification of precious stones has undergone a significant transformation, from traditional methods relying on visual traits to modern techniques employing scientific precision. This evolution reflects the growing complexity and sophistication of the gemstone market and consumer demands for transparency and quality assurance.
Traditional methods, rooted in visual and physical experience, provide a foundation for general identification and informal valuation. These methods primarily focus on observable physical characteristics such as colour, translucency, and hardness. For instance, gems were often grouped by their general appearance or how they felt and looked to the naked eye or simple tools.
Gems were also distinguished using colour categories or terms like “first water” to describe clarity and brilliance (e.g., the brightest, most transparent stones being "first water"). Traditional naming was often based on colour varieties within species—for example, ruby is the red variety of the corundum species, while sapphires are other corundum colours. Identification methods included simple tests such as scratching for hardness and basic observation of luster or inclusions, often supplemented by provenance and historical usage.
Modern gemology, however, uses scientific and technical criteria with precise instruments to classify gemstones. The primary classification starts with chemical composition and crystal structure. For example, diamonds are identified by their carbon makeup and cubic crystal system, while rubies and sapphires are varieties of aluminium oxide (corundum).
Gemologists employ detailed optical and physical measurements, including refractive index, birefringence, dispersion, specific gravity, hardness, cleavage and fracture patterns, pleochroism (colour changes at different angles), luminescence and absorption spectra. Modern classification also documents colour with hue, tone, and saturation precisely. For coloured diamonds, base colour, intensity, and colour distribution are rigorously graded since these heavily impact value.
Advanced techniques detect treatments or enhancements (e.g., oiling of emeralds) and trace geographic origin, which are critical for valuation and investment decisions. Certification from institutes like GIA or SSEF provides independent verification of natural origin, treatment level, and quality parameters, which traditional methods could not quantify as accurately.
The key differences between traditional and modern methods lie in their basis of classification, precision, identification tools, treatment detection, origin determination, valuation impact, and documentation. While traditional methods are qualitative and subjective, modern methods are quantitative and objective. Traditional methods rely on the naked eye, simple tools, and basic tests, while modern methods employ spectrometers, refractometers, microscopes, and advanced spectroscopy.
In terms of treatment detection, traditional methods are limited or nonexistent, while modern methods can detect a wide range of enhancements. Origin determination is rarely possible with traditional methods, but modern methods can pinpoint geographic sourcing based on microscopic and spectral markers. Valuation is mainly based on visible traits and provenance with traditional methods, while modern methods are based on scientific grading, certification, and treatment status, enhancing market confidence and pricing accuracy.
The evolution from traditional to modern methods has brought about a more accurate identification, treatment detection, origin certification, and reliable valuation, especially for high-value or investment-grade gemstones. Silicates, Oxides, and Carbonates are the three main gemstone families, each with unique characteristics. Understanding essential properties of gemstones, such as colour, hardness, luster, density, and specific gravity, can enhance appreciation and buying decisions.
Science has played a significant role in the transformation of gemology, shifting the focus from qualitative and subjective traditional methods to quantitative and objective modern techniques. This shift impacts various aspects of gemstone study, such as health-and-wellness, fitness-and-exercise, and nutrition, due to the increased knowledge about trace elements found in gemstones, which can have potential health benefits. For instance, certain gemstones like tourmaline are known for their bio-electricity properties, promoting well-being and maintaining fitness levels. Additionally, understanding the chemical composition of gemstones through modern methods can influence nutrition choices, as people may become more aware of the elements present in their gemstone jewelry. In the realm of health-and-wellness, this increased knowledge can lead to a more holistic approach to well-being, incorporating gemstones into lifestyle and dietary choices.
