Clear zircons are semi-precious gems found in small clusters in all igneous and metamorphic stone layers. At 25, it has the highest material value of any type of zircon - all types of colored zircon, while still semi-precious, have a material value of only 20.
In real life, high-quality colorless zircon is commonly used to make imitation diamonds. Its higher value may be intended to reflect this.
[SOLID_DENSITY:4650] Common to zircons. Range is 4600 - 4700