A Brief Tutorial on how to identify Rough Diamonds

Step:1 –  Identify the Shape of the Stone?

Shape, polygon

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Step:2 –  Identify the hardness of the Stone?


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It’s without a doubt that every diamond, rough or refined, is the hardest among all gemstones. This gem has the highest rating on the Mohs scale of hardness which ranks minerals from softest to hardest. But if you have a stone, how will you test for its hardness level?

Well, don’t scratch a glass using the suspected stone. On the Mohs scale, glass has a rating of 5.5 which means that most stones looking like a diamond can scratch it. Additionally, they are more common compared to diamonds, so the test will not be reliable.

To get good results, scratch corundum. Surprisingly, the stone has a rating of 9 on the Mohs scale and includes ruby and sapphires. If your stone scratches corundum, there are high chances that it’s a diamond. Alternately you can obtain a Carborundum Scribe or Tool and use this to try and scratch your specimen?

However, there are some metals like cubic zirconia and moissanite which are scratch-resistant. So, the hardness test is not as reliable as other tests like the thermal test.

Step:3 – The Water Flotation Method

  • Fill a clear and normal-sized drinking glass and fill it with water to a 3/4 level.
  • Then drop the stone you have into the glass.
  • If it sinks, the stone is a genuine raw diamond. But if it floats, it’s fake.

NB# We will talk about the process for Step:4 – Thermal Testing in our next Blog, feel free to
ask any questions through the forum provided herein!
Until then, stay safe and COVID-19 free!


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