New Delhi, Aug. 9 -- Buying your first coloured gemstone is unlike buying almost any other piece of jewellery. Unlike diamonds, which are assessed using a standardised grading system, coloured gemstones are valued for their individuality. Every emerald, ruby or sapphire is one of a kind, shaped over millions of years beneath the Earth's surface.

Their rarity and beauty often come with a substantial price tag, making the purchase as much a financial investment as an emotional one. Understanding the factors that determine a gemstone's quality and value can help you buy with confidence, and choose a piece you'll cherish for decades.

Colour is one of the most important factors to consider when buying a coloured gemstone. Look for an even di...