4 - C's

CARAT:

Carat is the unit of measurement for the physical weight of a diamond or moissanite. 

COLOR: 

DEF - Colorless 

GHI - Near Colorless

JKL - Slight yellow tint

CUT:

Diamond or Moissanite cut is how well a diamond or moissanite is cut and polished, including how well-proportioned the stone is, it's depth and symmetry.  IT DETERMINES HOW MUCH LIGHT THE STONE REFLECTS.  Very good cuts are quite similar to Excellent cuts.  The stone may have great color, clarity and carat, but if it reflects only a little light it will be dull and lifeless, while a stone with a great or excellent cut will emanate fire, sparkle and allurement.   

CLARITY:

Clarity is the quality of a stone.  It's the visual appearance of internal characteristics such as inclusions, and surface defects, called blemishes (black spots/marks). 

FL / IF = Flawless

VVS1, VVS2 = Very very small inclusion 1 or 2

VS1, VS2 = Very small inclusion 1 or 2

SI1, SI2, SI3 = Small inclusion 1 or 2 or 3

I1, I2, I3 = Inclusion 1 or 2 or 3