Crystal and diamond are different. They have different molecular structures, different hardness and different refraction to light. In the light, diamonds will be brighter. And the price of crystal and diamond is also very different. 1. Crystal is a member of the seasonal family and one of the most common minerals. Usually formed in igneous rocks, metamorphic rocks and sedimentary rocks, the chemical formula is Sio2, and the Mohs hardness is 7. The end of the crystal is rhombohedral or pyramid-shaped, and the crystal face is usually striped and glassy, with rich inclusions. Generally speaking, the purer and brighter the color, the higher the clarity and refractive index, and the higher the value of the crystal. 3. The main component of diamond is carbon (C), with a content of 96%-99.9%. Even pure diamonds contain 0.00 1% impurities. Impurities in diamond include silicon, aluminum, calcium, magnesium, manganese, titanium, chromium, nitrogen and so on. 4. Diamonds usually contain mineral inclusions, such as magnetite, ilmenite, garnet, chrome diopside, olivine and graphite. First of all, diamond is one of the hardest stones known.