On average, the retail price for one carat diamonds can be anywhere between $2,000 to $16,000, and between $8,000 to $72,000 for two carat diamonds . And of course, the retail price and the resale value of a diamond are very different things.

Dubai is deemed as one of the cheapest places to buy diamonds and rightly so. There's a reason that it is regarded as one of the world's top three diamond trading centers—the other two being India and Belgium.

In general, diamonds do not increase significantly in value over time. Outside of a small number of rare or colored diamonds, the vast majority of diamonds have decreased slightly in value over the last few years, making them a poor investment from a price appreciation perspective.

On average, you can expect the cost of a 2 carat diamond to widely vary depending on its shape, cut quality, clarity, color, and whether it's a naturally mined or lab diamond. The varying cost can range from $5,000 to $50,000 or more.