The misleading myth of the precious and semi-precious distinction
We often categorize gems into 'precious' and 'semi-precious' based on ancient Greek traditions. But in the modern market, this hierarchy is often an illusion. A common garnet can sometimes command a higher price than a mid-quality emerald, proving that rarity doesn't always dictate value.
The traditional Western classification, rooted in ancient Greek history, separates stones into precious (diamond, ruby, sapphire, and emerald) and semi-precious. This distinction was originally based on the rarity and extreme hardness of these stones, which typically score between 8 and 10 on the Mohs scale. However, modern gemology reveals that this nomenclature is commercially misleading. While the terms might reflect desirability, they fail to reflect actual market value. For instance, the green garnet known as tsavorite can be significantly more expensive than a standard emerald.
The true identity of a gemstone is found in its chemical composition and atomic structure. Many gems are crystals classified by systems like cubic or monoclinic. A single mineral species can produce various colorful varieties through tiny impurities; for example, the mineral beryl can become emerald if chromium is present, but becomes aquamarine if iron is introduced. Even more striking is the relationship between ruby and sapphire: both are varieties of the mineral corundum, but the presence of specific impurities determines whether the stone appears red or blue.
Valuation is a complex interplay of supply, demand, and physical characteristics. While diamonds are graded using a standardized 10x magnification system developed by the GIA in the 1950s, many other gemstones are still evaluated with the naked eye. Beyond color and clarity, experts look for 'optical phenomena' like asterism (star effects) or pleochroism. The global industry for colored gemstones is a massive economic force, valued at approximately US$1.55 billion in 2023, with projections suggesting it will reach $4.46 billion by 2033.
Source: Gemstone
