They can be created in various colors, so as to replicate natural colored diamonds.       American diamonds are really popular because of their durability, diamond-like qualities, and low cost. Hence, most people tend to choose American diamond rings these days. It can get challenging for even experts to differentiate natural diamonds from cubic zirconia stones, so imagine what a lay buyer would be up for. Below are some major differences that let you tell the two apart. Thermal Conductivity Diamonds are good conductors of heat and electricity, whereas, American diamonds are thermal insulators. Hence, you can spot cubic zirconia diamonds by measuring their thermal conductivity using appropriate devices. Hardness It is a known fact that diamonds are the hardest gemstone, ranking at 10 on the Mohs scale. Even though cubic zirconia stones exhibit a similar decent hardness, this reaches up to only 8 on the same scale. This means the latter is less durable when compared to the former.