Scientists first managed to create synthetic, or lab-grown, diamonds in the middle of the twentieth century. Like natural diamonds, synthetic stones are made of compressed carbon and share all the same chemical and physical properties. This means that they look and act exactly the same. Some of the synthetic diamonds made in the last few years are so similar to mined diamonds that gemologists need the help of advanced scanners to tell the difference. This means that no one will be able to tell just from looking if a stone is natural or lab-grown. This extraordinary similarity has led to concern that dishonest jewelers would try to sell lab diamonds as natural. To combat this fear, strict laws were enacted that require all diamond sellers to clearly disclose whether or not their diamond inventory is synthetic. If you are buying from a reputable dealer, you shouldn’t worry. If your diamond comes with a certificate from a grading laboratory, that document will say if the stone is natural or not.