EX-VG hpht treated diamonds high pressure high temperature diamond
Parameters of high pressure high temperature diamond
| Code # | Grade | Carat Weight | Clarity | Size |
| 04A | A | 0.2-0.4ct | VVS VS | 3.0-4.0mm |
| 06A | A | 0.4-0.6ct | VVS VS | 4.0-4.5mm |
| 08A | A | 0.6-0.8ct | VVS-SI1 | 4.0-5.0mm |
| 08B | B | 0.6-0.8ct | SI1-SI2 | 4.0-5.0mm |
| 08C | C | 0.6-0.8ct | SI2-I1 | 4.0-5.0mm |
| 08D | D | 0.6-0.8ct | I1-I3 | 4.0-5.0mm |
| 10A | A | 0.8-1.0ct | VVS-SI1 | 4.5-5.5mm |
| 10B | B | 0.8-1.0ct | SI1-SI2 | 4.5-5.5mm |
| 10C | C | 0.8-1.0ct | SI2-I1 | 4.5-5.5mm |
| 10D | D | 0.8-1.0ct | I1-I3 | 4.5-5.5mm |
| 15A | A | 1.0-1.5ct | VVS-SI1 | 5.0-6.0mm |
| 15B | B | 1.0-1.5ct | SI1-SI2 | 5.0-6.0mm |
| 15C | C | 1.0-1.5ct | SI2-I1 | 5.0-6.0mm |
| 15D | D | 1.0-1.5ct | I1-I3 | 5.0-6.0mm |
| 20A | A | 1.5-2.0ct | VVS-SI1 | 5.5-6.5mm |
| 20B | B | 1.5-2.0ct | SI1-SI2 | 5.5-6.5mm |
| 20C | C | 1.5-2.0ct | SI2-I1 | 5.5-6.5mm |
| 20D | D | 1.5-2.0ct | I1-I3 | 5.5-6.5mm |
| 25A | A | 2.0-2.5ct | VVS-SI1 | 6.5-7.5mm |
| 25B | B | 2.0-2.5ct | SI1-SI2 | 6.5-7.5mm |
| 25C | C | 2.0-2.5ct | SI2-I1 | 6.5-7.5mm |
| 25D | D | 2.0-2.5ct | I1-I3 | 6.5-7.5mm |
| 30A | A | 2.5-3.0ct | VVS-SI1 | 7.0-8.0mm |
| 30B | B | 2.5-3.0ct | SI1-SI2 | 7.0-8.0mm |
| 30C | C | 2.5-3.0ct | SI2-I1 | 7.0-8.0mm |
| 30D | D | 2.5-3.0ct | I1-I3 | 7.0-8.0mm |
| 35A | A | 3.0-3.5ct | VVS-SI1 | 7.0-8.5mm |
| 35B | B | 3.0-3.5ct | SI1-SI2 | 7.0-8.5mm |
| 35C | C | 3.0-3.5ct | SI2-I1 | 7.0-8.5mm |
| 35D | D | 3.0-3.5ct | I1-I3 | 7.0-8.5mm |
| 40A | A | 3.5-4.0ct | VVS-SI1 | 8.5-9.0mm |
| 40B | B | 3.5-4.0ct | SI1-SI2 | 8.5-9.0mm |
| 40C | C | 3.5-4.0ct | SI2-I1 | 8.5-9.0mm |
| 40D | D | 3.5-4.0ct | I1-I3 | 8.5-9.0mm |
| 50A | A | 4.0-5.0ct | VVS-SI1 | 7.5-9.5mm |
| 50B | B | 4.0-5.0ct | SI1-SI2 | 7.5-9.5mm |
| 60A | A | 5.0-6.0ct | VVS-SI1 | 8.5-10mm |
| 60B | B | 5.0-6.0ct | SI1-SI2 | 8.5-10mm |
| 70A | A | 6.0-7.0ct | VVS-SI1 | 9.0-10.5mm |
| 70B | B | 6.0-7.0ct | SI1-SI2 | 9.0-10.5mm |
| 80A | A | 7.0-8.0ct | VVS-SI1 | 9.0-11mm |
| 80B | B | 7.0-8.0ct | SI1-SI2 | 9.0-11mm |
| 80+A | A | 8.0ct + | VVS-SI1 | 9mm+ |
| 80+B | B | 8.0ct + | SI1-SI2 | 9mm+ |
4C Standard of high pressure high temperature diamond
Color
High pressure high temperature diamond color is graded in a standardized viewing environment.Gemologists analyze color in the D to Z color range with the diamond placed upside down, viewed through the side, to facilitate a neutral view.
Clarity
Grades clarity of high pressure high temperature diamond according to internationally accepted standards at 10X magnification, according to the visibility, size, number, location and nature of internal and surface characteristics at that magnification.
Cut
Gemologists overall proportions, measurements and facet angles are compared with studies of brightness, fire, scintillation and pattern to determine the Cut Grade of the hpht treated diamonds.
Carat weight
The first stage in high pressure high temperature diamond grading is weighing the diamond. Carat weight is the standard weight unit for gemstones. Diamond grading are to two decimal places to ensure accuracy.
