The term "4Cs" refers to the four parameters used to determine a diamond's price. These parameters are:

1. Carat: The carat measures a diamond's weight. Diamonds are measured in very small weights like 0.01 carats up to larger weights like 5 carats or more. There are 100 points in 1 carat, meaning a 0.50 carat diamond equals 50 points. Larger diamonds have a higher price because they are considered more rare. Bigger diamonds require more rough material and additional cutting work to maintain quality. Large diamonds are also harder to source, further increasing cost.
2. Color: A diamond's color affects pricing. The most expensive diamonds are perfectly colorless white stones with no hue. Diamonds with a high color grade are rarer and require precise cutting to ensure maximum brilliance. The greater the color, the more valuable the stone. Color scales rank diamonds by color level. The highest grade is D, then E then F for the best colors, descending down the scale through G-H-I-J-K-L.
3. Clarity: Clarity refers to a diamond's quality based on flaws. The cleanest diamonds with zero imperfections give the sharpest, brightest appearance. As clarity increases, light refracts optimally off the stone. Flawless diamonds are extremely rare and require specialized cutting to maintain perfection - so higher clarity equals higher cost.
4. Cut: A diamond's cut refers to the quality of workmanship transforming a rough diamond into a polished gem. Diamonds with excellent cut allow light to enter and exit the stone in the most ideal way, maximizing brilliance. Precise cutting is difficult and necessitates great skill. So the more perfect the cut, the more valuable the diamond.

Each of these factors impacts price. Therefore, diamonds can vary greatly in cost. When size is large, color is colorless, clarity is high, and cut is exceptional - the diamond will be supremely expensive.