Gemstones 101: Diamonds, Sapphires & Beyond

Gemstones 101: Diamonds, Sapphires & Beyond

Walk into any jewelry store and you'll be greeted by dozens of stones in every color imaginable. Some are classics. Some are trends. Some are worth far more per carat than a diamond. Knowing the basics helps you buy smarter — and more meaningfully.

Diamonds: The Most Gifted Stone in the World

Diamonds earn their place at the top through brilliance, durability (10 on the Mohs hardness scale — the highest possible), and the depth of meaning behind them. They're graded on four attributes, the '4 Cs':

•       Cut – How well the diamond's facets interact with light. The biggest driver of how spectacular a diamond looks in real life.

•       Color – Rated D (colorless) to Z (yellow). D–G is effectively colorless to the naked eye.

•       Clarity – The number and visibility of inclusions. VS2 or SI1 is 'eye-clean' for most buyers.

•       Carat – The weight of the stone (not its physical size). More isn't always better.

Sapphires: The Durable Classic

Sapphires score 9 on the Mohs scale, making them second only to diamonds in hardness — and ideal for everyday wear. They come in every color, though blue remains the most iconic. Sri Lankan ('Ceylon') sapphires are prized for their vivid cornflower blue. Princess Catherine's engagement ring is a blue sapphire, which has driven significant interest in the stone over the past decade.

Rubies: The Rarest of the Precious Stones

Fine rubies — particularly those from Burma (now Myanmar) — are among the rarest and most valuable gemstones on earth. They can exceed diamonds in per-carat price. Color is everything: the most prized shade is a vivid, pure red known as 'pigeon's blood.' Rubies rate 9 on the Mohs scale and hold up well to daily wear.

Emeralds: Bold Color, Distinctive Character

Emeralds are the green gemstone. They rate 7.5–8 on the Mohs scale — durable but requiring slightly more care than diamonds, rubies, or sapphires. Nearly all natural emeralds contain inclusions, which the trade calls 'jardin' (French for garden). This is considered normal and expected — unlike diamonds, where inclusions lower the value significantly.

Colombian emeralds are the most coveted for their rich, warm green hue.

Semi-Precious Stones: More Color, More Accessibility

Amethyst, topaz, garnet, tourmaline, aquamarine, and others deliver stunning color at price points that make fine jewelry more accessible. They're ideal for:

•       Birthstone jewelry — a deeply personal gifting choice

•       Fashion-forward pieces where color is the statement

•       Layering and stacking sets

•       Budget-conscious buyers who don't want to compromise on craftsmanship

Stone Hardness at a Glance

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Read next in this series: Post 3 - How to Buy Fine Jewelry for Any Occasion