Earth's Treasury. Used with permission.
Yellow Sapphire Faceted from United States
Can you guess which of these stones have undergone heat treatment? The pink and yellow stones have natural colors, and the green and blue stones have undergone heat treatment to enhance clarity and intensify color. © Earth's Treasury. Used with permission.
Article: Why We Love Montana Sapphires and Yogo Sapphires
Credit: Earth’s Treasury
| Gemstone | Sapphire, Corundum |
| Natural or man made | Natural |
| Origin | United States |
| Origin details | Yogo, Montana |
| Gem State | Faceted |
| Color | Yellow, Green, Blue, Pink |
| Transparency | Transparent |