Asia's Biggest Virtual Gemstone Inventory

Experience ZCOVA’s vibrant colors of 100% natural certified gemstones before choosing your unique sapphire, ruby or emerald gemstone. Admire the details in 360° HD & 10x magnified to really get to know your gemstone. 

Learn the value of your gemstone to make an informed decision before making a purchase.

Browse Gemstones

What type of gemstones does ZCOVA sell?

Our virtual gemstone inventory includes 8 varieties of gemstones: Ruby, Emerald, Sapphire, Fancy Sapphire, Alexandrite, Spinel, Tourmaline, and Tsavorite. However, you may contact us to source other types of gemstones not listed on our website.

Understanding Gemstone Grades

What do you need to know when buying gemstones and how are gemstones graded? Unlike diamond 4Cs, there is no universal grading system for colored gemstones at the moment. At ZCOVA, we use ICL’s grading system to determine a gemstone’s color intensity, clarity, and cut consistently.

Gemstone Color

Color is the most important factor determining the quality of the Gemstone. With a full rainbow spectrum of colors, it makes them an ideal stone that adds vibrancy and character to your jewellery collection. Bear in mind that Gemstone colors also come in different hues.

Once you’ve picked your ideal colour, you should look into the Intensity of the colour. This is what determines the long-term value of your stone. Vivid is the most sought after colour intensity because it reaches the optimal balance of colour hue and saturation. 

For example, the Vivid colour of sapphires and rubies are so popular that they have coined the names Royal Blue Sapphires and Pigeon Blood Rubies.

Dark: Moderate to strong saturation of color with a very dark tone.
Deep: Moderate to strong saturation with a medium dark to dark tone.
Vivid: Vivid saturation with a medium to medium dark tone. This is considered the finest intensity of color for a colored gemstone.
Intense: Moderate saturation of color with a medium light tone.
Medium Intense: Moderate saturation of color with a light tone.
Light: Slightly greyish or brownish saturation of color with a light tone.
Very Light: Greyish saturation of color with a very light tone.

 

Gemstone Carat Weight

1 carat = 0.2 grams = 100 points

The size of a gemstone is mainly determined by carat weight. One carat is equal to 0.2 grams and is often divided through a point system, where 100 points make up a single carat unit. The larger the gemstone, the rarer and more valuable it becomes.

Due to their rarity, the price of certain gemstones increase exponentially with colour intensity and size. For example, a 10.0 carat ruby can be, on average, a hundred times more expensive than a 1.0 carat ruby.

 

Gemstone Clarity

Clarity refers to the amount of flaws or inclusions in a gemstone. Colored gemstones that are free of inclusions are very rare and visible inclusions are common and accepted. Gemstones are not expected to be free of inclusions when viewed at 10x magnification.

ICL classifies clarity for transparent colored gemstones into 6 different grades:

Eye Clean 1 (EC1): Free of inclusions to the unaided eye and very few inclusions visible while looking with a x10 power loupe. This is considered the finest clarity for colored gemstones.
Eye Clean 2 (EC2): Free of inclusions to the unaided eye.
Visible Inclusions 1 (VI1): Inclusions very slightly visible to the unaided eye.
Visible Inclusions 2 (VI2): Inclusions slightly visible to the unaided eye.
Included 1 (I1): Inclusions highly visible to the unaided eye.
Included 2 (I2): Inclusions very highly visible to the unaided eye.

 

Gemstone Origin

We tend to associate a product quality with its geographical origin. As for most products like watches and wine, this too is the case with gemstones.

The origin of a gemstone can affect its color, type of inclusions, and value. Certain gemstones like Burmese Rubies and Kashmir Sapphires are very rare, commanding premium prices in the international market.

 

Gemstone Treatment

Most gemstones are treated to improve their color or clarity. Naturally perfect gemstones are rare and expensive so heat treatment is very common and well accepted. It simply speeds up the process gemstones go through naturally and does not harm the stone.

There are several types of treatments such as:

H(F1): Heated (Minor residues)
H(F2): Heated (Moderate residues)
H(F3): Heated (Significant residues)
Minor oil clarity enhancement
Major oil clarity enhancement
Significant oil clarity enhancement

 

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