Gemstone Guide

A gemstone is roughly defined as a highly-prized mineral or other organic material that comes from the earth or ocean. Often categorized into precious and semi-precious classifications, gemstones come in various colors and structures and are found all over the globe. Buying a colored gemstone can sometimes be even more daunting compared to diamond jewelry; with so many different types of gemstones, the varying hues, characteristics, and styles can be overwhelming. We’re here to simplify it all for you. Choose your gemstone based on your personal preferences such as your lifestyle, favorite colors, and individual style, and you can’t go wrong.

When talking about gemstones, one often hears about a specific distinction: precious vs. semi-precious.  Currently, only four gemstones are considered precious – diamonds, emeralds, sapphires, and rubies. However, when gemologists and jewelers first started using the term, both pearls and opals were also considered precious. Even amethysts were listed as precious gemstones until early on in the 1800s, when large quantities of the mineral were found in South America, greatly decreasing its rarity. Qualifying a type of gemstone as precious or semi-precious depends on how beautiful, rare, and desirable it is, but the truth is it can often be fairly arbitrary. Tanzanite, for example, is a stunning and very rare gemstone found only in Tanzania, but it is listed as semi-precious. Some semi-precious gemstones can even demand a higher asking price than precious stones, depending on quality and size. Choosing a piece of gemstone jewelry, therefore, is a highly personal choice. Listen to your intuition and choose the gemstone that fits you best!


While gemstones are judged using a similar grading system as diamonds, each type is judged separately. For example, a sapphire is compared to other sapphires, never an emerald or aquamarine. When it comes to a gemstone’s color, three terms are often used: hue, tone, saturation. These three criteria help determine the value of a stone. Hue refers to which of the six colors (red, orange, yellow, green, blue, and violet) is exhibited by a stone. Gemstones that are tinted grey or brown are less valuable than those with more pure colors. Tone refers to how light or dark a particular hue is in a given gemstone, ranging from being very pale to almost black. Finally, saturation is also known as intensity and describes the amount of color possessed by a stone. A perfectly saturated emerald, for example, is a deep, bright green with no blue or yellow hue. It’s also important to note that some gemstones even span different hues – for example, tourmalines, garnets, and sapphires all come in blue, yellow, pink, and black hues.

Red Ruby, Mozambique Garnet

Pink Pink Sapphire, Rhodolite Garnet  

Yellow Yellow Sapphire, Citrine

Green Emerald, Bloodstone, Jade, Peridot

Blue Blue Sapphire, Aquamarine, Blue Chalcedony, Blue Spinel, Blue Zircon, Lapis

Purple Amethyst, Tanzanite

White Akoya Pearl, Freshwater Pearl, Mabe Pearl, South Sea Pearl, White Spinel, White Topaz, Moissanite, Opal

Brown Smoky Quartz

Black/Gray Tahitian Pearl, Onyx  


We sell a number of different shaped gemstone jewelry. Some of our most popular shapes include round, marquise, oval, pear, princess, and baguette. 

Gemstone Guide


Gems are cut in a variety of different ways. Transparent stones will often be cut with facets. Unlike diamonds, the facets are planned to maximize the color. Other stones like jade, opal, and onyx will be cut into a smooth domed shape known as a cabochon. While still other stones like cameos are intricately carved. 

Diamond Cuts


Similarly to diamonds, gemstones are also judged on their clarity. In other words, each stone is evaluated based on its internal and external imperfections called inclusions. Some gemstones, such as emeralds, are known for naturally having more inclusions than others. The more included or cloudy a gemstone is, the less valuable it tends to be. There are exceptions to this, such as star sapphires. These sapphires have inclusions which cause a reflection of a star-like pattern on the surface of the stone.

Diamond & Gemstone Size Ranges

Also like diamonds, gemstones are weighed in carats. One carat is equal to one-fifth of a gram or 0.007 of an ounce. It’s important to note that almost all gemstones have different densities, meaning that two different types of gemstones might be different sizes but could weigh the same. For example, rubies are denser gemstones than emeralds. As a result, a one carat ruby will be smaller than its one carat emerald counterpart.

accent .004 min.
0.01 .008 min.
0.015 .012 min.
0.02 .015 min.
0.025 .02 min.
0.03 .025 min.
0.04 .035 min.
0.05 .045 min.
0.06 .055 min.
0.07 .065 min.
0.08 .075 min.
1/10 0.09 min.
1/8 .11 min.
1/6 .14 min.
1/5 .18 min.
1/4 .23 min.
1/3 .29 min.
3/8 .37 min.
1/2 .45 min.
5/8 .60 min.
3/4 .66 min.
7/8 .84 min.
9/10 .90 min.
1 .96 min.
1 1/8 1.10 min.
1 1/6 1.14 min.
1 1/5 1.18 min.
1 1/4 1.23 min.
1 1/3 1.29 min.
1 3/8 1.37 min.
1 1/2 1.45 min.
1 5/8 1.60 min.
1 3/4 1.66 min.
1 7/8 1.84 min.
1 9/10 1.90 min.
2 1.96 min.
2 1/8 2.10 min.
2 1/6 2.14 min.
2 1/5 2.18 min.
2 1/4 2.23 min.
2 1/3 2.29 min.
2 3/8 2.37 min.
2 1/2 2.45 min.
2 5/8 2.60 min.
2 3/4 2.66 min.
2 7/8 2.84 min.
2 9/10 2.90 min.
3 2.96 min.
3 1/8 3.10 min.
3 1/6 3.14 min.
3 1/5 3.18 min.
3 1/4 3.23 min.
3 1/3 3.29 min.
3 3/8 3.37 min.
3 1/2 3.45 min.
3 5/8 3.60 min.
3 3/4 3.66 min.
3 7/8 3.84 min.
3 9/10 3.90 min.
4 3.96 min.
4 1/8 4.10 min.
4 1/6 4.14 min.
4 1/5 4.18 min.
4 1/4 4.23 min.
4 1/3 4.29 min.
4 3/8 4.37 min.
4 1/2 4.45 min.
4 5/8 4.60 min.
4 3/4 4.66 min.
4 7/8 4.84 min.
4 9/10 4.90 min.
5 4.96 min.
5 1/8 5.10 min.
5 1/6 5.14 min.
5 1/5 5.18 min.
5 1/4 5.23 min.
5 1/3 5.29 min.
5 3/8 5.37 min.
5 1/2 5.45 min.
5 5/8 5.60 min.
5 3/4 5.66 min.
5 7/8 5.84 min.
5 9/10 5.90 min.
6 5.96 min.
6 1/8 6.10 min.
6 1/6 6.14 min.
6 1/5 6.18 min.
6 1/4 6.23 min.
6 1/3 6.29 min.
6 3/8 6.37 min.
6 1/2 6.45 min.
6 5/8 6.60 min.
6 3/4 6.66 min.
6 7/8 6.84 min.
6 9/10 6.90 min.
7 6.96 min.

Gemstone Enhancement Codes

Published by the American Gem Trade Association.

Enhancement: Any treatment process other than cutting and polishing that improves the appearance (color/clarity/phenomena), durability, or availability of a gemstone.

N: The "N" symbol appears on the chart only for natural stones which are not currently known to be enhanced; however, the "N" symbol can also be used for other natural gemstones in the event that a gemstone has received no enhancement and the seller will provide a guarantee that there has been none.

E: The "E" symbol indicates that a gemstone has undergone its traditional enhancement process.

B Bleaching

The use of heat, light and/or other agents to lighten or remove a gemstone's color.

C Coating

The use of such surface enhancements as lacquering, enameling, inking, foiling, or sputtering of films to improve appearance, provide color, or add other special effects.

D Dyeing

The introduction of coloring matter into a gemstone to give it new color, intensify present color or improve color uniformity.

F Filling

The filling of surface-breaking cavities or fissures with colorless glass, plastic, solidified borax or similar substances. This process may improve durability, appearance, and/or add weight.

H Heating

The use of heat to effect desired alteration of color, clarity, and/or phenomena (if residue of foreign substances in open fractures is visible under properly illuminated 10X magnification HF should be used.

HP Heat & Pressure

The use of heat and pressure combined to effect desired alterations of color clarity and/or phemonena.

I Impregantion

The impregnation of a porous gemstone with a colorless agent (usually plastic) to improve durability and appearance.

L Lasering

The use of a laser and chemicals to reach and alter inclusions in diamonds.

O Oiling/Resin Infusion

The filling of surface-breaking fissures with colorless oil, wax, resin, or other colorless substances, except glass or plastic, to improve the gemstones appearance.

R Irradiation

The use of neutrons, gamma rays or beta particles (high energy electrons) to alter a gemstones color. The irradiation may be followed by a heating process.

U Diffusion

The use of chemicals in conjunction with high temperatures to produce artificial color and/or asterism-producing inclusions.

W Waxing/Oiling

The impregnation of a colorless wax, paraffin, and oil in porous opaque or translucent gemstones to improve appearance.

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