This is the question asked by every second person who at least once in life faced a choice between mined or synthetic diamonds. But it's better to specify the term “synthetic diamonds” since some readers may synonimize it with diamond substitute.
Synthetic, man made, lab-grown diamonds are the terms used to identify 100% diamonds which are grown in laboratories instead of being extracted from under the earth mantle. They shouldn't be mixed with cubic zirconia and moissanite, which are not diamond in terms of chemical composition, physical properties and even visual characteristics.
As the name says, synthetic diamonds are grown synthetically in the lab under similar conditions that are found in nature. This is exactly what makes them real. The scientists were able to recreate under-the-earth formation process in chambers, so now the customers actually have two options: mined diamonds and lab-grown diamonds.
But there is still one controversial issue – the price. Colorless synthetic diamonds cost pretty much the same as natural ones. However the difference is vividly seen when fancy colored gems are concerned, for example yellows are 4 times cheaper while for pink you will pay only 1/10 of natural diamond's price. Now it's time to answer the title question – why are synthetic diamonds so expensive? There are some common reasons for that:
1 – there is lots of science in there. The technology of growing diamonds is quite young, about 50 years only. Scientists spend much time to perfect the process to make synthetic diamonds more available for customers. But there are still some limits that engineers can't go beyond, for example the size of a gem. Man made diamonds are usually of smaller sizes, not exceeding 2 carats. Recent demands for larger gems show that there are still points for improvement.
2 – laboratory equipment is very expensive. This is sophisticated equipment that have to withstand extremely high temperature as well as high pressure similar to those taking place deep under the ground. When the risks are high the equipment should be reliable and this is not the point to save on.
3 – growing diamonds is a time-consuming process. Do you know that diamonds are grown separately, meaning that only one stone is grown at a time? Moreover, it takes a couple of days to cultivate a raw stone: from 3 to 14 depending on size and color.
Aside from the abovementioned reasons there are also materials, energy and labor that should be paid for. All these affect the price of man made diamonds. Then when raw stone is ready, it should be cut and graded drawing even more financial resources. That is why the costs for synthetically grown and mined stones are nearly the same.