Emerald

Inclusions are the norm, not the exception

Virtually every natural emerald contains visible inclusions, fissures, mineral crystals, and fluid pockets. The trade calls the resulting pattern jardin, French for garden.

This is a genuine difference in grading convention. An eye-visible inclusion that would drop a sapphire several clarity grades is simply expected in an emerald, and a flawless one at a normal price should raise your suspicion rather than your pulse.

Why the “emerald cut” is named after the stone

The rectangular step cut with clipped corners was developed for emeralds specifically, and for two practical reasons rather than aesthetic ones.

• Corners are where stones chip. Emerald is brittle and often fissured, so cutting the sharp corners away removes the most vulnerable points and gives a setting’s prongs something safer to hold.
• Broad flat facets suit color over sparkle. Emerald’s appeal is the depth and evenness of its green. Large step facets show that off, where the many small facets of a brilliant cut would break the color into flashes.

The cut has since been applied to diamonds and every other gem, but the shape exists because of what emerald is.

Color: the dominant value factor

As with ruby, color carries most of the value. The ideal is a pure, vivid green, medium to medium-dark in tone, with no brown or grey dulling it. A slight blue secondary hue is widely accepted and often admired; yellow secondary tones are less prized.

There is no single “best” origin, only different characters at different prices. To compare stones methodically, use our gemstone color guide.

Oiling: what it is and why it matters

Nearly all emeralds on the market are treated with oil or resin. Cedarwood oil, whose optical properties closely match beryl’s, seeps into surface-reaching fissures and makes them far less visible. The practice is centuries old and disclosed as standard.

What you need to know is the degree, which laboratories grade roughly as none, minor, moderate, or significant. It has a large effect on price: a stone graded “no oil” can be worth several times an otherwise identical one graded “significant.”

How to care for an emerald

At 7.5–8 on the Mohs scale emerald is reasonably hard, but hardness is not the issue, its fissures make it comparatively brittle. Treat it as the most delicate of the classic gemstones.

• Never use an ultrasonic or steam cleaner. Both can drive oil out of the fissures and can worsen an existing fracture. Warm water, mild soap, and a soft brush is the whole routine.
• Keep it away from heat and solvents. That includes leaving a ring on through household cleaning, and it includes jeweler’s heat, always tell anyone doing repair work that a stone is emerald.
• Choose a protective setting. Bezels and half-bezels shield the girdle and corners far better than exposed prongs.
• Think twice about an everyday ring. Emerald is a superb choice for earrings, pendants, and occasional rings. For a ring worn through manual work, sapphire at Mohs 9 is the more practical stone.