How to identify gemstones by color: Complete guide

One of the most famous gems, ruby gets its red color from the element chromium. Rubies have a warm, deep red tone with a faint fluorescence under UV light.

Much rarer than ruby, red beryl ranges from pinkish red to deep red. Under sunlight, it may show tiny eye-visible crystals inside.

There are several red varieties of garnet, including almandine and pyrope garnet, with pyralspite garnets tending to show more of a purple-red. Garnets have high refractive indexes that produce a fiery glow.

Inclusions may resemble fingerprints inside red spinels. Spinels exhibit pleochroism, causing the red color to change based on viewing angle.

Red tourmalines like rubellite have strong pleochroism shifting between pinkish-red and purplish-red.

After blue diamond, sapphire is gem quality corundum in shades from medium dark blue to violetish blue. Blue sapphires show red fluorescence under UV.

Ranging from purple-blue to blue-violet, this variety of zoisite displays strong pleochroism. Tanzanite often shows banded striations inside.

One of just a few gems occurring naturally in blue, topaz tends toward a cool, icy light blue. Topaz has highly visible cleavage planes.

Aquamarine has a crisp medium blue tone without gray or green, unlike many other blue gems. This beryl variety shows almost no pleochroism.

The quintessential green gem, emerald is chromium-containing beryl in a rich green color, often with gardenia or mossy secondary hues. Emeralds commonly have inclusions.

From yellow-green to bluish-green, tourmaline occurs in almost any green shade. Green tourmaline exhibits strong pleochroism from bluish to yellowish tones.

One of few gems found naturally in a bright lime green, peridot is an olivine mineral. Peridot has visible cleavage and inclusions, and shows some pleochroism in deeper shades.

Though less common than red or orange garnets, varieties like demantoid and tsavorite form in green. Green garnet tends to display spindle-like inclusions.

Made of quartz, citrine ranges from pale yellow to a deep amber depending on iron content. Natural citrine points show horizontal striations.

Corundum occurs not just in blue but also yellow, with yellow sapphire tending toward golden tones. Yellow sapphire exhibits red fluorescence under UV light.

Ranging from pastel yellow to vibrant yellow, heliodor beryl tends to be more yellow than greenish. It shows almost no pleochroism or fluorescence.

Yellow topaz occurs in lemon, golden, and amber yellow varieties. Topaz has highly visible cleavage planes inside.

Most valuable of the yellow gems, yellow diamond colors result from nitrogen impurities. Fancy vivid yellow diamonds with intense saturation are most prized.

Ranging from orange to reddish-orange, this garnet variety has higher refractive indexes for more fire. It often forms with small mineral inclusions inside.

Imperial topaz is prized for its pinkish orange to orangey red tones reminiscent of a sunset. It typically displays cleavage planes.

Sapphires not only occur in blue and yellow, but also orange when trace elements like iron and titanium are present. Orange sapphire shows red fluorescence under UV.

Zircon can form in vivid orange as well as brownish red shades. It has high dispersion that splits white light dramatically into spectral colors.

As quartz, amethyst ranges from light reddish purple to deep violet. Natural amethyst, especially crystals, form with horizontal banding.

This extremely rare chrysoberyl variety shows a dramatic color change from reddish purple in sunlight to violetish green in indoor lighting.

Sapphires form not only in single colors but also bi-colors like purple and orange. Purple sapphires exhibit red fluorescence under UV.

Inclined toward red-violet to purplish-red tones, purple spinel exhibits strong pleochroism in those shades.

Caused by distortions in a diamond’s crystal lattice, natural pink diamonds range from purplish pink to orangey pink in tone. They rank among the most prized diamond colors.

Ranging from light to hot pink, pink sapphires get their color from trace elements like chromium. They show red fluorescence under UV.

Pale pink to light violet pink in tone, this gem-quality spodumene shows strong pleochroism between those shades.

Ranging from peach pink to vibrant pink and formed of beryl, morganite often displays banded twinning striations inside.

Caused by dense inclusions, black diamonds rank among the rarest diamond colors. The inclusions give black diamonds an opaque, black appearance.

An opaque jet black variety of spinel with a smooth polish, black spinel rates among the darkest spinels. It has a rich history in jewelry dating back centuries.

Most common variety of diamond results in a crystalline transparency. Very high-quality white diamonds with perfect transparency are most valued.

Essentially clear corundum, white sapphires lack the color of blue ones. They possess exceptional brilliance and hardness.

Transparent topaz tends toward a “silver” white color. It is more affordable than diamond or sapphire while retaining exceptional shine.

The colorless transparent form of beryl has exceptional clarity but lacks the sparkle of diamonds.

Made of hydrated silica, opal diffracts light into flashes of spectral color like miniature rainbows. These play-of-color flashes distinguish precious opal.

Pleochroism in iolite causes one gem facet to appear blue while another facet shifts to violetish gray. This dichroic effect makes iolite seem multicolor.

Though red garnets are most common, garnet also forms in green, orange, yellow, purple and even color-changing varieties in a single gem family.