Meet the Four Cs

 Colour 顏色                                                                                                                                                                                                                                        
Often many people think of diamonds as colourless.  In fact, colourless diamonds are quite rare.  When diamond graders and experts appraise the colour of the diamond, they are looking for a lack of colour or degree of transparency.  The less colour the diamond has, the more desirable and higher its colour grade.  The most valuable white diamonds contain no traces of colour and are composed purely of carbon. 
    Diamonds contain traces of nitrogen that come in many colour like yellow or brown or other elements that may affect their transparency.  Diamonds often appear as pale yellow.  That is why a diamond’s colour grade is based on its lack of colour.  The less colour the diamond has, the more desirable and higher its colour grade.  A colour grade of D (Colourless) is the highest while Z (light) is the lowest.
      Other most valuable diamonds that possess natural colour is called Fancy-coloured diamond. They come in red; pink; blue; green; orange; brown and black or even multi-coloured in some cases.



      Diamond Colour Scale  鑽石顏色分級

      D COLOURLESS Completely Colourless. Highest Colour Grade. Extremely Rare.

      Minute traces of colour that can be detected by an expertGemologist.

      A rare diamond.


      Difficult to detect unless compared diamonds side-by-side of bettergrades.A terrific value compare to higher grades diamond.


      Difficult to detect unless compared diamonds side-by-side of better grades. A terrific value compare to higher grades diamond.

      (K)(M) Faint

      Noticeable colour with traces of pale yellow.

      (N)(R) Very Light  Diamond within this grade will be distinctly yellow in color.




      Diamond within this grade will be distinctly yellow in color


      A hint of colour in diamond is so slight that only trained eyes are able to notice it, and it certainly does not detract from the beauty of the diamond.

      Clarity 淨度                                                                                                                                                                                                                                             
      The internal features of diamonds are called inclusions and surface irregularities, called blemishes.  They are called clarity characteristics.  Diamond with the least and smallest clarity characteristics receive the highest clarity grades.  Many of these clarity characteristics are microscopic, and do not affect a diamond’s beauty in any perceptible way.  There are no two diamonds in this world that have precisely the same clarity characteristics and that makes diamond so precious and unique of its own.

      Clarity grade has several categories that affect the price of a diamond


      Flawless: No internal or external clarity characteristics. Extremely rare.


      Internal Flawless: No internal clarity characteristics. Extremely rare.

      VVS1, VVS2

      Very, Very Slightly Included: Very difficult to detect clarity characteristics under 10X magnification. An exceptional quality diamond.

      VS1, VS2

      Very Slightly Included: Clarity characteristics are not particularly visible under the unaided eye. Less expensive than VVS1 and VVS2 grades but brilliant quality.

      SI1, SI2

      Slightly Included: Clarity characteristics are visible to see under the 10X magnification and maybe noticeable under the unaided eye.  A diamond of good value.

      I1, I2, I3

      Included: Obvious to see clarity characteristics under 10X magnification. MOHSTEN does not carry diamonds of this grade.


      Cut 鑽石切割

      Cut is one of the most important in the 4Cs because this can have an overall impact on the beauty of the diamond.  An objective measure of a diamond’s light performance is its’ cut grade, resulting in a display of three essential diamond characteristics: brilliance, fire and scintillation. 

        Whilst light ray strikes a diamond, it either reflects off the surface or enters.  A diamond’s proportions decide how it interacts with light and its finish show off the diamond’s beauty.  If the diamond is cut too deep, light escapes out of the sides while if it is cut too shallow, light leaks out of the bottom.


         Carat  克拉                                                                                                                                                                                                                                             
        We use metric carats, abbreviated “cts” to measure diamond weights.

          The diamond/gem weight international measurement is one carat equals one-fifth of a gram (0.200 g).  The division of metric carat is 100 points.  A point abbreviated “pt.” is one hundredth of a carat (0.01ct).  Hence, 50 points is equal to 1/2 carat.
            Carat is specifically a measure of a diamond’s weight however by itself may not precisely reflect a diamond’s size.  To have a better understanding of diamond size, two conditions should be considered in conjunction with carat weight.  1. It is essential to measure the distance across the top of the diamond. 2. The cut grade of the diamond.
            我們使用公制克拉(縮寫為“cts”)來衡量鑽石重量。 鑽石/寶石重量的國際計量單位是一克拉等於五分之一克(0.200 克)。

            公制克拉的劃分是100分。一個點縮寫為“pt”。是百分之一克拉 (0.01ct)。
            因此,50 分等於 1/2 克拉。克拉是鑽石重量的具體衡量標準,
            1. 必須測量鑽石頂部的距離。 2. 鑽石的切工等級。
            Fluorescence 螢光
            Fluorescence refers to how a diamond responds when exposed to ultra-violet light. 
              Some diamonds will glow into different colour.  Most of the time, diamond will glow into blue but on rare occasions, they can glow white, yellow, green or even red.  In the Gemological Institute of America diamond report, the fluorescence is graded as “None”, “Faint”, “Medium” or “Strong”.  Most diamond fluorescence is not detectable under normal daylight and therefore this does not affects its’ overall appearance.  For diamonds with a higher colour grade coupled with a strong fluorescence may appear a little hazy while diamonds with lower colour grade and strong fluorescence may appear whiter than they really are.