Assessing Value of Gems (Part 1)

Assessing Value of Gems

Natural Gems and minerals (and jewellery of course!) are beautiful, intriguing and rare. We all know they hold a certain value and is something that everyone would like to own a piece.

So how do we know what value and how to value a beautiful piece of gem?

First of all, assessing value of gems requires a lot of experience. Experience can come in the form of buying and selling, or learning from the books and history of previous transactions, for example in auctions.

In this 3-part series of assessing value of gems, we will not be showing exactly HOW to assess value. But we will give you an insight on the factors to understand and consider, before you begin to assess the value of the gems.

What gives gems a value? What makes gems valuable?

Gems are valuable because of the following factors:

  • Beauty
  • Rarity
  • Durability
  • Demand
  • Tradition
  • Portability


To begin, beauty is the first attribute that we can see with our naked eyes. For most part, the 4Cs have been a big contributor for understanding the beauty of a gem. These are: Carat weight, Clarity, Colour and Cut. However, the 4Cs probably applies more to transparent, faceted gems. Other gem materials like jadeite-jade and nephrite-jade has its own unique grading system. Therefore, the beauty of a gem may also be described as the ‘quality’ of a gem.

Assessing value of gems
A set of blue sapphires put together for colour comparison. Colour is an important factor when assessing value of gems.


Rarity means uncommon, or unusual. Diamonds are rare because the yield of mining production is very low. For every 5carat total weight of diamonds mined, approximately 300 tons of ore needs to be processed. Similarly for rubies and sapphires, in many mining countries, the mining technique is still quite manual, although some are semi-automatic. Kashmir sapphires for example, are mined from very harsh conditions. Hence, explaining its rarity.

There are also some gemstones which are rare because of its phenomenal optical effects. In order to achieve perfect chatoyancy (cat’s-eye) or asterism (star), it depends on the rough material as well as the lapidary. When the best of the two comes together, the fashioned gemstone becomes very rare.

assessing value of afghanistan emeralds
Rough Afghanistan emeralds. These emeralds tend to be slightly lighter in colour and not as saturated as those of Columbian emeralds. However, beautiful green pieces are also very hard to come by. The value is in its ‘hard to come by’ factor.



Gemstones are valuable because of its durability. It doesn’t get damaged easily and therefore keeps its quality the same for a very very long time. Therefore, some pieces of gems and jewellery can be kept and passed down from one generation to another. Family heirlooms have very intrinsic value that is very hard to quantify. When assessing value of gemstones, we also will look at how well it has kept its durability, i.e. how well it has been maintain at its highest quality.

Durability involves a few factors: hardness, toughness and stability (to light, heat and chemicals). We will discuss these in the future blog posts.

Meanwhile, we do not want to see chips and scratches on our gems!

assessing value by duarbility
This amethyst has polishing marks on the surface. This is because it has a hardness of only 6.


Assessing value of gemstones to be continued…

We have discussed three reasons why gemstones are valuable. In fact, these factors applies also to diamonds and minerals, except for some variations in the details.

In the second part of this topic, we will continue to discuss on why gemstones are valuable.

The Basics of Understanding Gemstones (Part 2)

Understanding Gemstones Part II


Let’s recap the first three categories of gemstones in Part I:

  1. Crystal Systems
  2. Organic Gem Materials
  3. Phenomenal Gems

The next three categories of gem materials are as below:

  1. Rare Gems
  2. Imitation
  3. Synthetic

Rare Gems

Perhaps this can be better described as unusual or uncommon gems. Some examples are like kornerupine and sillimanite. These gems are often not as popular because they either come in small quantities, or they are not as attractive as the others like rubies and sapphires. Nevertheless they are still very beautiful nature’s creations. Other examples shown in the pictures below are some collections we have in The Gem Museum.

This is an old collection we have. Small and fragile.
Crocite, USA. This is another small piece we have that is very fragile and is crumbling apart.
Wulfenite, USA. Wulfenite is a lead molybdate mineral with the formula PbMoO4.



Technically, these should not be described as “gems”. These materials are mainly man-made and artificial materials. The term ‘imitation’ means to ‘simulate’. It could be using a natural material to simulate another natural material of a higher value. An example is using serpentine to imitate a more valuable jadeite. Most of the time, due to the low cost and high consistency in production, glass is the most common material used to imitate many other gemstones. Green glass to imitate jade or emerald, red glass to imitate ruby and blue glass to imitate sapphire.

jade imitation
Dyed quartzite imitating jadeite-jade.
Natural Jadeite-jade.
Serpentine carving that is often mistaken as Jadeite-jade.


Many companies out there are selling synthetic materials, but not explaining clearly to consumers what synthetic really means. The emphasis is always on the fact that synthetic materials have exactly the same physical and chemical properties as the natural counterpart. These materials are considered artificial as they are “lab-grown” and sold in the market for less than half the price most of the time. Synthetic materials can be produced in large quantities at any one time. This includes diamonds. As such, the rarity factor of a ‘gem’ is hardly applicable for these materials. Although they are also beautiful, the value of these materials can never match up to a natural gemstone of the same quality.

natural rubies
A set of natural rubies put together to compare its colour quality.
synthetic rubies
These are synthetic rubies that have the same chemical and physical properties as natural rubies.

The Basics of Understanding Gemstones (Part 1)

The Definition of “Gemmology”.

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!

Celebrating our 2nd Anniversary

“No valleys, no mountaintops.” – B.C. Forbes

On 1 June 2017, we celebrated The Gem Museum’s 2nd Anniversary. We are grateful to everyone who has been supporting us in various ways since we opened in 2015.

For the purpose of our 2nd anniversary, we have invited the press and media from various publishers in Singapore and around the region to grace a special event on 10 unique diamonds.

10 unique diamonds showcased on our anniversary
Setup for the 10 unique diamonds

Before the 10 unique diamonds were presented, we brought our guests through a journey from “Mine to Market”. Special thanks to Mr. Tay Thye Sun for contributing many of the gems and rock samples to educate about geology and gem formation, the first section of the museum. Here, we have a “Rock Garden”, featuring some of our collections from different countries such as Australia, China, Indonesia and Madagascar.

Geology & Gem Formation
Geology & Gem Formation

Of the 10 unique diamonds, the most special diamond is a 1.5ct heart-shaped Chameleon Diamond. We also want to give a special shoutout to our friends from Hong Kong, who are avid diamond collectors, Mr. Si and family. Without which we would not have such great fun showing a beautiful piece of diamond to our guests.

Chameleon Diamond
Heart-shaped chameleon diamond

At the end of the event, there was good interaction with questions and answers. Some of the questions include “How does one become a gemmologist?”, “Which is the most valuable gemstone or diamonds we have seen?” etc. It was a great time of sharing knowledge and experiences.

exhibit demonstration
Mr. Tay Kunming speaking with the guests

Once again, we sincerely thank everyone who had helped us and supported us in one way or another throughout the last two years.

The next exciting event coming up would be the “Moons & Stars” exhibition that we will be setting up during the Singapore’s Night Festival along the Bras Basah and Bugis (BBB) district. Do look out for updates in the next few months!