How to Buy a Gemstone
Beautiful, bright and brilliant, these are the words used to describe gemstones; buying gemstones might seem fairly easy, but there is a lot more to it than meets the eye. An eye-catching gemstone is usually what you look to buy, but why do some gemstones cost more than others? Why is one gem variety cheaper than the other even though they both look practically the same? What five features a buyer should look at to see if they are getting a prized possession or a lemon? All of these questions will be answered in the following article.
Gemstones come in virtually every colour of the spectrum. What many people do not know is one gem variety can have many different hues. A
good example would be sapphires; they do not only come in blue, but yellow, pink as a range of colours – some exhibiting unusual phenomena. Other gem varieties that also express this characteristic are tourmaline garnet, and diamonds which are also available in almost every colour.
What you also might not realize is that there are many gems available in each hue, where some are at surprisingly affordable prices. Prices for the different gem varieties are affected by rarity, durability, and popularity. Lesser-known gems are sometimes just as beautiful and inexpensive.
How Colour affects the value
The most important value factor in any gem variety is colour. Colour is
evaluated in similar ways for each gem. Hue isn’t the only factor that matters in a gem’s colour. A colour’s tone and saturation are also important. The most sought after gemstones are brighter, more vivid colours with a medium tone.
An example, the most valued blue is a cornflower blue with a hint of purple - usually a pale sky blue or blackish blue would be less expensive. Gems that are very pale, very dark, or whose hues are tinged with brown or gray are less valuable.
One should also note, colour preference can also be personal. Just because the colour is not the most sought after doesn’t mean it might not
be the most beautiful to you.
The colour of most gems is affected by different light sources. Blue sapphires look the best illuminated by an office fluorescent light, while rubies look better under ordinary household incandescent light. You should always look at a gem you are considering to purchase in different lights, especially in the light you plan to wear it in the most.
Some gemstones such as alexandrite, change colour. Sapphire and chrysoberyl show patterns such as stars and cat’s eyes, respectively when a spotlight shines on them. Others like opal exhibit a play of colour,
while moonstones display adularesence. Gemstones with special optical effects such as the ones described earlier are called phenomenal gems.
Another important factor when picking out a gemstone is clarity. Clarity is a measure of freedom from the tiny internal characteristics known as inclusions.
Many gemstones have inclusions because of the way gemstones form in the earth. In a way they are considered birthmarks. Generally it is rare to find a gem with very few small inclusions or inclusions invisible to the naked eye. Keep in mind that inclusions are responsible for many of the
optical phenomena seen above. So for gems like Cat’s Eye Chrysoberyl and Star Sapphires, inclusions usually add value.
On the other hand gems such as emerald, and red tourmaline, almost always have visible inclusions so the lack of clarity does not detract from its value. Make sure inclusions are not located at the edge or the corner of the stone as this might reduce durability.
Clarity has the most impact on pale colour stones as inclusions are much easier to see when the colour is pale.
Inclusions & Value
You might think of inclusions as imperfections which detract from a gemstone’s beauty. Some gemstones are more lovely and valuable because of their inclusions.
Gemstones with inclusions that make them interesting to gemologist and collectors are:
- Demantoid garnet with a horsetail inclusion
- An emerald with a three-phase inclusion
- Amber that contains insects from the deep past
Rarity & Carat Weight
Gems are sold by weight not by size. The measurement used is a carat which is 1/5 of a gram.
Some gems rarely occur in larger sizes. Among them are emerald, ruby, sapphire, tsavorite garnet, alexandrite, and spinel. The price per carat will jump for a larger stone compared a smaller stone.
On the other hand amethyst, citrine, blue topaz, and amber are more available in larger sizes so gemstones with a larger size would be priced similar to stones of smaller size.
A one carat emerald and a one carat ruby are the same by carat weight but not the same size, because each is a different mineral with a different density.
Cut & Beauty
Gems are a masterpiece of nature but it takes a skilled gem cutter to display its brilliance and inner beauty. Each gemstone handles light differently due to the unique optical properties of its crystal structure.
There are two things to understand when talking about cut: the three dimensional shape in which the gemstone is fashioned and the quality of the cut. In other words how well the gem’s shape delivers brilliance and
To judge a cut, look at how the gem returns light to the eye. The best cuts are symmetrical and return light across the entire surface of the gemstone, with no dark or washed areas.