How can we determine Diamonds by Cut, Clarity, Color and Size?

There are set standard which can determine diamond clarity. Usually gemologists use 10X microscope along with naked eye analysis of inclusion to determine diamond clarity. The presence of inclusion in diamonds, its location determine the diamond clarity grading. Here are some guidelines by which we can determine the quality of diamonds. Here they are following:

Remember to focus on these 4Cs before determining the quality of a good diamond. They can help you a lot in defining the best one. 
The 4Cs of diamond quality are:

• Color
• Clarity
• Cut
• Carat Weight (size)
  In color, white brilliant is the most ideal. Here is color chart

Elements of the GIA diamond color grading scale are:

• Colorless (D-F)
• Near Colorless (G-J)
• Faint (K-M)
• Very Light (N-R)
• Light (S-Z)
• n clarity,

Diamond clarity grades under 10x magnification include:

• Flawless (FL): It means that diamond has no inclusions or blemishes.
• Internally Flawless (IF):  It means that diamonds have no internal inclusions. They may have slight surface blemishes visible under 10x magnification.
• Very, Very Slightly Included (VVS1) and (VVS2): That means that diamond has minute inclusions which is difficult to see, even under 10x magnification.
• Very Slightly Included (VS1) and (VS2); These type of diamonds have minor inclusions. These are sometimes detected very easily under 10x magnification. This is invisible to the naked eye, however.
• Slightly Included (SI1) and (SI2): These type of diamonds have noticeable inclusions under magnification. This type can be visible to the unaided eye.
• Included (I1), (I2), and (I3): These type of diamonds have obvious inclusions easily visible to the naked eye with potential durability risk the further down the scale you go.

Cut Quality can be determined by following:-

The perfect cut encompasses these three optical effects, making your diamond stunning:

• Brightness. This is the white light reflection of a diamond.
• Fire. Fire refers to the flashes of colors, the diamond displays as light refracts due to a prismatic effect.
• Scintillation. This factor is the play between the light and dark areas of your diamond.

The cut quality for AGS grading ranges from:

• Ideal Cut (0)
• Excellent Cut (1)
• Very Good Cut (2)
• Good Cut (3 to 4)
• Fair Cut (5 to 7)
• Poor Cut (8 to 10)

The top diamond graders in the U.S. and Europe are:

• Gemological Institute of America (GIA)
• American Gemological Society (AGS)
• European Gemological Laboratory (EGL)
• Diamond High Council (HRD)
• International Gemological Institute (IGI)
• International Confederation of Jewelry, Silverware, Diamonds, Pearls, and Stones (CIBJO)