| Rare earth element distributions in the zircons and garnets strongly suggest that the zircon overgrowths formed in equilibrium with garnet. |
| Reducing iron oxide levels to 0.07 percent will allow the zircon to meet premium grade specifications. |
| A honey-colored to brown zircon continues to be mined that can be heat-treated to lighten the color. |
| The zircon, hyacinth, jacinth, or jargoon belong to the tetragonal system of crystallization. |
| Even resistant minerals such as zircon have been found to be etched by bacteria. |
| Although blue corundum, zircon, and tourmaline occur in Colorado, they are not known to produce gems. |
