1. Chemical Composition Difference: Diamonds are primarily composed of carbon, whereas zircon is mainly made up of zirconium silicate.2. Crystal Structure Difference: Diamonds belong to the isometric crystal system and typically occur as single crystals, commonly in the shapes of octahedra and dodecahedra. Zircon, on the other hand, belongs to the tetragonal crystal system and is often found in a combination of square prisms and square double pyramids, with varying angles of inclination.3. Color Difference: Diamonds come in a range of colors, from colorless to light yellow (including brown and gray) in the colorless series, and various colors in the colored series. Zircon exhibits a broader spectrum of colors, including colorless, blue, green, yellow, brown, orange, red, and purple, among others.4. Luster Difference: Diamonds have a characteristic adamantine luster. Zircon exhibits a range of lusters, from adamantine to glassy.5. Origin of Production Difference: Diamonds are processed from rough diamonds. Zircon is typically produced as a minor mineral in igneous rocks.6. Hardness Difference: Diamonds are the hardest natural mineral, with a hardness of 10. Zircon has a hardness ranging from 7.5 to 8.7. Melting Point Difference: The melting point of diamonds is between 3550 and 4000 degrees Celsius. For zircon, it is between 2340 and 2550 degrees Celsius.