How Much and What Type of Inclusions does a GRS Certified 4 to 5 carat Unheated & Heated Vivid Blue Royal Blue Sri Lanka Sapphire have? [Video]

In the video above, I compared the prices between one unheated (100% natural) and two heated GRS certified 4 to 5 carat, Vivid ‘Royal Blue’ Sri Lankan Sapphire.

All three sapphires are 4 to 5 carat each, are GRS certified, vivid ‘royal blue’ from Sri Lanka.  The cost difference is between unheated stone and two heated – The unheated sapphire cost is US$8,000 per carat while the two heated stones cost is US$3,500 per carat

The method I use to determine the value of any gemstone is by first categorizing the stone based on the 4Cs + OT method.

The six criteria I have summarized in bullet form are below.

All three stones have similar criteria as indicated in GRS certification:


We use the 4C’s + OT method:

All three sapphire’s GRS Certificate copies are provided below, which states four criteria like ‘carat weight, color grade, origin, and treatment level.’

  • Color –
    • GRS grade – Vivid Blue “Royal-Blue” which I completely agree with in my eyes 
  • Carat Weight –
    • Above 4 carats to 5 carats (4.06 carats, 4.14 carats & 5.12 carats)
  • Origin –
    • Sri Lanka
  • Treatment levels –
    • No Indication of thermal treatment which means 100% natural unheated sapphire (4.06 carat stone)
    • H – which means normal heat treatment (for two stones – 4.14 carats & 5.12 carats)

Clarity and cut grade must be determine by the naked eye as the labs does not provide this detail.   This will effect the gemstones brilliance, sparkle and scintillation.  

  • Clarity (Two criteria) –
    • Inclusions – 90 to 100% Eye-clean or ‘Very Slight’ Inclusions
    • Transparency – 100% Transparent and not cloudy (not translucent or opaque)
  • Cut Grade –
    • Very Good to Excellent for all three sapphires


  • 4.06 carats – unheated sapphire –  US$8,000 per carat or US$32,480
  • 4.14 carats – heated sapphire – US$3,500 per carat or US$14,490
  • 5.12 cates – heated sapphire – US$3,500 per carat or US$17,920



UNHEATED – No indication of heat treatment inclusions in Sri Lanka Sapphire

  • Intact, fine, needle-like Silk (rutile needles) intersecting at 60 degrees angle.  
  • Unaltered mineral inclusions, crystals, and needles

Video shows all the above inclusions.   Also, I have provided some images of these inclusions below.

HEATED – Normal Heat Treatment inclusions in Sri Lanka Sapphire

  • Broken silk or partially “reabsorbed” rutile needles
  • Inkspots from the heating process

I have provided some images of these inclusions below.


Other resources to see typical Sri Lankan inclusions I recommend checking the following websites:

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