Graining is the subterranean growth process of the diamonds. The diamond crystals are formed deep underground over millions of years until assuming their final form.
The diamond is made of lines of matter which are layered atop one another, making the diamond an extremely hard material. The lines which match the crystal’s structure are a remnant of its unique growth process. These lines are called graining lines or growth lines.
When these lines on a diamond are prominent and brightly colored, they can impair the diamond’s clarity, but sometimes they are not noticeable except at certain angles.
