Gemstone Guide

What to Consider When Buying Gemstones and Diamonds

Buying a gemstone or diamond can be a daunting and confusing business, but don’t worry, we’re here to help guide you through it.

What to Look for in Gemstones

The Four Cs

There are many factors that determine the value of a gemstone but the most important four are color, carat, clarity and cut. The color of a gemstone affects how rare and desireable it is. The more carats, the bigger the rock. Clarity refers to the number of tiny flaws (inclusions) in a gemstone, with flawless being the most expensive. Finally, the way a gemstone is cut affects how well it sparkles; the better it’s cut, the more brilliantly it will shine.

Origin and Treatment

In addition, where the gemstone came from and whether it has had any treatment to enhance the color or clarity also affects the prices. The more treatment a stone has had, the less valuable it becomes.

Expert Advice Needed

Unlike diamonds, the beauty and difficulty of buying a colored gemstone is determining what the actual color is. You really need to see it in person. Similarly, there are no standard definitions on how clarity is defined.  Due to these issues, the only way to purchase colored gemstones online is to have a professional look at the actual stone.

The Big Three


Rubies are generally the most expensive colored gemstone per carat.


From orange red to purple red and pure red.


High quality stones bigger than 5 carats are extremely rare. Available in commercial grades up to 10 carats.


Many rubies are heat treated to optimize their color. Some may be heated with flux or filled with lead glass to fill inclusions.


Emeralds have been highly valued and sought after throughout history.


Strong blue green, blue green, slightly blue green, green and slightly yellow green.


Fine stones of more than 8 carats are rare. Commercial grade stones come in sizes of up to 20 carats or even more.


Almost all emeralds are oiled. Some have resins added and inclusion filling can also occur. These treatments help to enhance the clarity of emeralds which commonly have many natural inclusions.


Sought after sapphires have become the most popular gemstone in the U.S.


Sapphires come in a wide range of colors in all seven primary hues. Blue is the most often found, sought after and expensive.


High quality stones over 20 carats are rare. Available in lower grades in very big sizes.


Improving the color of sapphires through heat treatment is very common.

How to Choose a Diamond Engagement Ring

Decide How Much You Want to Spend

Everyone’s heard the one-to-two months salary rule, but don’t take that too seriously. At the end of the day a diamond ring should be a symbol of your love and needn’t break the bank.

Go for Something that Fits Her Style

Have a look at her jewelry collection for inspiration: Is she more modern or traditional? Does she prefer bold or simple with a clean design? Does she favor small or big rings? What color jewelry (white gold, yellow gold, rose gold, two-tone or platinum) does she tend to wear?

Decide on the Ring

If you want to get some solid insider advice, consider confiding in her friends and family. Don’t worry, you can always propose with a simple design and then choose the perfect ring together afterwards.

Choose a Diamond Shape

Round diamonds offer a wonderful sparkle and are a classic choice. Square diamonds have a more uniform sparkle. If you want to go for something beautiful, unique and a little less ordinary, consider pear or oval-shapes.

Consider “the Four C’s”

Cut, clarity, color and carat will all affect the cost of your diamond with big, colorless and flawless diamonds the most expensive. For an engagement ring, the cut is always very important.