Which Colored Gemstone Should You Choose?

A diamond is graded against a universal scale. A colored stone is chosen because it speaks to you.

That is the pleasure of colored gemstones: you are choosing color, and color is personal. Every stone below is set in our fine jewelry and worn and loved every day. Here is what makes each one special — and how to choose with confidence.

How each stone wears

Two qualities matter: hardness, how well a stone resists scratching (the Mohs scale, 1 to 10), and toughness, how well it resists chipping. The right setting and a little everyday care do the rest.

The stones, and what makes each one special

Sapphire

Blue is the classic, but sapphire occurs in nearly every color except red — pink sapphire in particular has become a favorite for engagement rings. What you are paying for is saturation: a vivid, evenly distributed color is worth far more than a pale or patchy one of the same size. At 9 on the Mohs scale, sapphire is the most forgiving colored stone there is, made for a lifetime of daily wear.

Ruby

Chemically the same mineral as sapphire — corundum — colored red by chromium, with the same 9 hardness. A ruby of rich, glowing red is among the most prized gems in the world by carat, and one of the most romantic.

Emerald

The green of emerald is like no other. Nearly every emerald contains natural inclusions, called the jardin — the garden — and in emerald they are part of its character, not a flaw. Emerald rings have been treasured for centuries; we set ours to protect the stone, so its color can be worn and enjoyed. Clean it with warm soapy water, never an ultrasonic.

Amethyst

Purple quartz, and one of the best values in fine jewelry: rich, saturated color in generous sizes, at prices sapphire never reaches. At 7 on the Mohs scale, it wears beautifully in rings.

Garnet

A deep, warm red — and one of the great secrets of colored stones. A well-cut garnet with strong saturation reads richer than many rubies, at a fraction of the price, and wears well in rings, earrings and bracelets alike.

Blue topaz

Bright, clean, and available in generous sizes for very little. London blue is the deepest tone; Swiss blue is brighter and more electric. At 8 on the Mohs scale, it is at home in rings as well as earrings.

Peridot

A luminous yellow-green found in no other common gem, and the birthstone of August. Lovely in rings, earrings and pendants — simply take it off for the gym or the garden.

Tourmaline

Tourmaline has one of the widest color ranges of any gem, sometimes several colors in a single crystal. Pink tourmaline is a favorite in earrings, and at 7 to 7.5 on the Mohs scale it wears well in rings too. It shares the October birthstone with opal.

Black onyx

Not a transparent gem but a dense black chalcedony — one of the toughest gem materials there is, which is why it has been a classic signet-ring stone for centuries. It provides a contrast no transparent stone can, which is why we set it with diamond and pair it with white pearl. Black onyx is a signature of the house.

Moonstone

Valued for adularescence — the blue-white glow that floats across the surface as it moves. It is one of the three June birthstones, alongside pearl and alexandrite. We set it where it can glow and stay protected: earrings, pendants, and bezel-set rings.

What drives the price

For colored stones the order is different from diamonds. Color comes first — saturation and evenness account for most of the value. Clarity second, with different expectations per stone (an emerald is judged against emeralds, not against sapphire). Cut third, which decides how evenly the color reads. Carat last — size amplifies whatever the stone already is.

This is why a 2 carat pale sapphire can cost less than a 1 carat vivid one — and why we choose for color first.

Treatments, plainly

Most colored stones in fine jewelry are treated, and that is normal. Heating sapphire and ruby to bring out their color is an ancient, stable, permanent practice accepted throughout the trade. Other treatments — oiling emerald, for example — are standard as well. What matters is that you know what you are buying, and we tell you plainly.

A note on lab-created stones

Lab-created gems are chemically identical to mined ones and cost far less. We use created emerald in some designs and say so plainly on the product page. Whether that matters is a personal judgment, not a quality one — but you should always know which you are buying.

The same logic applies to diamonds, discussed in lab-grown vs. natural diamonds.

How we choose

We select colored stones for saturation and clarity, set them in 14K and 18K gold, and inspect and approve every piece in New York before it carries our name. Our gemstone pieces run from the hundreds into the low thousands — rings, earrings, bracelets, and pendants across every stone above.

Every piece ships free, with 60-day returns and a complimentary annual inspection and cleaning — so the stone you choose today looks as good in ten years.

Not sure which stone suits what you have in mind? Reach us at sales@isaacwestman.com or 1-347-389-0766.

Browse colored gemstone jewelry, gemstone rings, and gemstone bracelets.

The best jewels make the best gifts.

ISAAC WESTMAN® · New York · Founded 1982