SIMILAR TO A formula  in school, we probably all know the 4 Cs by heart. For those who don´t know, the 4 C´s help you to define a diamond (carat, cut, color, clarity).  When looking for an engagement ring, you have to find the perfect diamond size, especially according to your budget. While the cut, color and the clarity also define a diamond´s price, there is a rule (with exceptions of course): the bigger the diamond = the higher the carat = the pricier the gemstone.