Carat (often abbreviated as 'ct') denotes a diamond's weight rather than its size, impacting its value. While larger-carat diamonds are typically more valuable, two diamonds of the same carat weight can differ significantly in price due to variations in their cut, color, and clarity.

The color grade of a diamond indicates the extent of its coloration, ranging from D to J. Higher grades approach colorlessness and exhibit superior brilliance. 

Clarity refers to the presence of imperfections in diamonds, categorized as inclusions (internal) and blemishes (external). Higher clarity grades signify fewer imperfections, enhancing transparency and brilliance.

The diamond cut refers to how the diamond is faceted to maximize its brilliance and light reflection. It encompasses the diamond’s proportions, symmetry, and polish (surface condition), which collectively determine its ability to exhibit optimal aesthetic appeal and excellent light performance.