Assessing Value of Gems (Part 2)

3 More Gems Factors

The first 3 factors to understand and consider before you begin to assess the value of the gems are:

  • Beauty
  • Rarity
  • Durability

Read about the first 3 factors here!

 

Value of Gems

  • Demand

Because of the beauty and rarity of gemstones, there is a demand. In different cultures, there is a demand for different variety of gems.

For example, in the Asian culture, we value the imperial green jadeite-jade. 98% of jadeite-jade is produced in one mine in Myanmar, Pharkant. As the imperial green quality is very rare, the supply is hard to meet the demand. Hence, this material is highly sought after.

 

jade
Green Imperial Jadeite-jade is very sought after. One way to give more value to a piece of jewellery, yet still affordable, is to use smaller pieces of high quality jade.

 

Another example is diamond. “Diamonds are a girls’ best friend.” This slogan by the marketing agency of De Beers has popularized the use of diamond in an engagement ring so much that it created an in-flux of demand for diamonds.

diamond
2 oval yellow diamonds with 1.50ct D colour Diamond set in 18K white gold.

High quality diamonds like a 5 carat, D colour, Internally Flawless and excellent cut piece is rare and hard to come by.

 

 

  • Tradition

The royal crown jewels are an important set of jewellery because it tells the history of a nation. The royalties are an icon to the nation and perhaps even a role example for others around the world.

crown jewels
Imperial State Crown, UK Photo Source: https://en.wikipedia.org/wiki/Crown_Jewels_of_the_United_Kingdom

When Prince William and Prince Harry got married, the trend of using a blue sapphire and aquamarine for an engagement ring went up tremendously. During these seasons, the demand increased. Some quality-grades of the gems were very difficult to get too.

 

proposal ring
Emerald cut aquamarine from Afghanistan. Prince Harry’s wife, Megan Markle received an aquamarine ring for proposal.

 

  • Portability

This is an interesting factor. Portability can also be understood as “transportability”. Gemstones are small and lightweight. It is even better when set into a piece of jewellery. One can wear it and travel around the world (with insurance of course!).

24 carat Colombian Emerald worth USD120,000 can be worn from one place to another.

One of the stories that we have heard from our Director, Mr. Tay Thye Sun, happened in 1997. It was during the Asian financial crisis. A lady from Indonesia who looked really normal and unnoticed came into his gem testing laboratory.

She look a piece of diamond for testing and evaluation and found that it was about USD5000 at that time. She then went on to test another diamond of about 1 carat in weight. This diamond was evaluated to be worth about USD15,000 at that time.

The next thing we know, she took out a small pouch and poured out all the diamonds in that pouch. All in all, the diamonds in that small little pouch was worth a few million dollars (there were 5 carat diamonds too).

So now we can see how portability can affect the value of gems! In fact, gemstones are seen to be very good commodities to “invest” in to keep value because of this factor!

 

In Conclusion…

Knowing these 6 factors can then help you to understand the value of gems in a practical manner. In the 3rd part of this series, we will share with you some practical things you can do to gain market experience.

Gemstones that form in the Earth’s mantle

Only two gemstones form in the Earth’s mantle

diamonds can be found in the earth's mantle

Yellow Diamond from South Africa, a country known for its diamond mines. 

(Photo by Eric Nathan/Alamy, taken from National Geographic)

 

Together with diamonds, peridots are also found in the earth's mantleOlivine (Peridot) at the Natural History Museum, London.

(Photo by Aram Dulyan, via Wikimedia Commons, taken from International Gem Society)

 

Most gemstones form in the Earth’s crust. Only two gemstones form in the Earth’s mantle – the diamond and the peridot. These are gems that crystallise at extremely high temperatures.

 Fun fact: Diamonds may actually be the most plentiful crystals in the earth, but they just aren’t the easiest to reach

Diamonds are formed in the earth’s mantle.

Diamonds crystallise in very hot and fluid magma about 110 to 150 miles (117 to 241 kilometres) below the Earth’s surface. Because of the heat and fluidity, this magma is able to force a pathway up through the Earth’s crust at greater speeds and violence than other volcanic eruptions! These are called “kimberlite pipes”.

A simplified diagram of kimberlite pipe in earth's mantle and surface

  1. Magma pocket comes in contact with a weak area in crust.
  2. A quick explosion results, carrying diamond-bearing magma from the lower mantle to the surface. During the eruption, a cone builds on surface.
  3. The pipe eventually cools, leaving carrot shaped pipe.
  4. The cone quickly erodes away, leaving the diamond-bearing rocks where people can reach them.

(Diagram and description taken from International Gem Society)

 

If the rising of magma were any slower, the diamonds would likely not survive, as the changing temperatures and pressure would likely have caused them to vaporise or recrystallise as graphite.

This video shows a simple set up at The Gem Museum. It shows the formation and mining of diamonds in the world.

Peridot

Geologists believe that peridot first crystallises on rocks floating in the mantle about 20 to 25 miles (32 to 89 kilometres) below the Earth’s surface. Then an explosive eruption brings them near the Earth’s surface, and weathering and erosion brings them close enough to be mined and found.

 

Earth's mantle forms peridots
Peridot crystal from Pakistan (The Gem Museum)

 

peridot forms in earth's mantle
Peridot crystals from Lisu Village, North Myanmar. (The Gem Museum)

References / Further reading:

Gem formation – International Gem Society

Where did those gemstones come from – ThermoFisher Scientific

The Basics of Understanding Gemstones (Part 1)

The Definition of “Gemmology”.

gemmology
dʒɛˈmɒlədʒi/
noun
noun: gemology
  1. the study of precious stones.

Our Mission…

The Gem Museum’s mission is to help people appreciate the value of gems through understanding quality and learning about authenticity. Therefore in this two part series, we would like to introduce to you 6 categories of gems and gem materials.

1) Crystal Systems

First of all, here is a need to first understand crystals, in order to understand the structural and optical properties of gemstones. It is from here that you can identify the gemstones. Most miners, for example, in Thailand, Sri Lanka or Myanmar, they do not have formal education. They grow up in mines and start mining for gems at a very young age. However, they could probably identify the rough gem materials, simply based on their observations of structural and optical properties of gems.

gemstone crystals
An overview of the 7 Crystal systems
cubic system
Examples of cubic system: Diamond, spinel, garnet, fluorite
Aquamarine is in the Hexagonal crystal system.

2) Organic Gem Materials

Most people do not realise that these are considered gems too. One of the classification of gem materials is ‘organic’ gems. Organic gems mean that the gem materials was formed through process involving life organisms and some examples are amber, pearls, and even petrified wood.

Fossilized Coral

3) Phenomenal Gems

Finally, in this post, we will talk about some gemstones with special optical effects. Phenomenal Gems have very unusual optical properties. Not all gem materials exhibit optical phenomenal. The optical phenomenal of a gem material could be due to internal reflection of the inclusions, such as cat’s-eye. Another possibility is the structural arrangement of the material, such as moonstones that give the moonlight sheen, described as “Adularescence”. Most of all, our gem museum has a unique collection of double stars and we are still in the midst of searching for more double stars too!

star sapphire
A star sapphire set in a ring.
Labradorite exhibits an optical effect that is due to interference caused by the layering of the material.

In conclusion, there are many ways to categorise and classify gem materials. Hence, look out for the next part of this blog, so that you can understand more about gems and gemstone materials!