


There is no known blue diamond with a completely flawless (F) clarity grading, although several are known which are graded Internally Flawless (IF). However, the most valuable of blue diamonds also exhibit the highest clarity grades. Color is considered the absolute most important criterion in grading a blue diamond and determining its value. The same four basic parameters that govern the grading of all gemstones are used to grade blue diamonds–the four Cs of Connoisseurship: color, clarity, cut and carat weight. Blue diamonds belong to a subcategory of diamonds called fancy color diamonds, the generic name for diamonds that exhibit intense color.

They are colored blue by trace amounts of boron that contaminate the crystalline lattice structure. Transparent to subtransparent to translucentīlue diamond is a type of diamond which exhibits all of the same inherent properties of the mineral except with the additional element of blue color in the stone. Closeup of the Hope Diamond, a famous dark blue diamond
