The Colored Stone Story

What are colored stones?
Colored stones refer to any gem other than diamond. Some diamonds are colored, but colored diamonds are not considered colored stones.

What are the attributes of colored stones?
A colored stone possesses any of these three key characteristics: beauty, durability and rarity. An ideal colored stone has all three characteristics.

Why do colored stones look the way they do?
A number of factors contribute to the overall appearance of colored stones. These include color, transparency, lustre, brilliance, dispersion, scintillation, clarity and cut.

What is the difference between precious stones and semi-precious stones?
In the past, the term ‘precious stone’ referred to diamond, emerald, ruby and sapphire, while ‘semi-precious stone’ were anything other than these. Then, precious and semi-precious stones indicated relative value – the former being more valuable. Today, these descriptions have little meaning in terms of value, since all colored stones come in a variety of qualities. For example, a low quality ruby may sell for as little as USD1 per carat, while a good quality demantoid garnet may fetch USD1,000 per carat.

Are colored stones durable?
In order to wear well and retain attractiveness colored stones should be durable. Durability includes hardness and toughness. Resistance to scratching is referred to as hardness. Some colored stones are soft and may be easily scratched, thereby losing their attractiveness. Ideally a colored stone should be harder than dust particles, which may be fine particles of quartz (hardness=7) found in the air. Colored stones with hardness greater than quartz include ruby, sapphire, topaz, tourmaline, spinel and garnet. These are the most valuable. Resistance to breakage is referred to as toughness, and this depends on colored stone’s structure. Extremely tough gems are usually aggregates such as jadeite and nephrite.

Is there a relationship between quality and price?
In a perfect world price would directly relate to quality, weight and rarity. The real world is far from perfect. Market factors may have an impact on prices, as does quality.

What is colored stone treatment?
Colored stone treatment is a common term. It describes different ways to improve the beauty of colored stones. Colored stones have been enhanced for thousands of years. The truth is there isn’t enough top quality colored stones being mined to meet demand. Enhancement increases supply, ensuring a constant flow of colored stones which we can afford and enjoy. If in doubt about a colored stone, always consult a reputed gem testing laboratory.