Olivine is usually green in color but can also be yellow-green, greenish yellow, or brown. It is transparent to translucent with a glassy luster and a hardness between 6.5 and 7.0. It is the only common igneous mineral with these properties. The properties of olivine are summarized in the table.
Pallasite peridot: This is one of the most incredible gemstones. It is a piece of gem-quality olivine (peridot) from a pallasite meteorite, and it has been faceted into a wonderful little gemstone. This may be the most scarce gem material on Earth – but it actually originated in space. This stone is 2.85 millimeters in diameter and weighs about ten points.
| Physical Properties of Olivine | |
| Chemical Classification | Silicate |
| Color | Usually olive green, but can be yellow-green to bright green; iron-rich specimens are brownish green to brown |
| Streak | Colorless |
| Luster | Vitreous |
| Diaphaneity | Transparent to translucent |
| Cleavage | Poor cleavage, brittle with conchoidal fracture |
| Mohs Hardness | 6.5 to 7 |
| Specific Gravity | 3.2 to 4.4 |
| Diagnostic Properties | Green color, vitreous luster, conchoidal fracture, granular texture |
| Chemical Composition | Typically (Mg, Fe)2SiO4. Ca, Mn, and Ni rarely occupy the Mg and Fe positions. |
| Crystal System | Orthorhombic |
| Uses | Gemstones, a declining use in bricks and refractory sand |