Diamonds are without a doubt among the most desired and sought-after stones in the world. Diamonds come in many forms, sizes, and prices, but some are significantly more valuable than others. If you're interested in luxury and high-end things, you should look into the world's most expensive diamonds. The most valuable diamonds in the world include the Sancy Diamond, Cenetary Diamond, Cullinan Diamond, Steinmetz Diamond, and Hope Diamond. And the Kohinoor Diamond is the King of Diamonds, as it is the most expensive diamond in the world. Kohinoor is considered the most valuable and priceless.