Peridot (likely, given the color and bead form)

Hardness: 6.5-7 on Mohs scale. Color: Green, ranging from yellowish-green to olive-green to brownish-green. Luster: Vitreous to oily. Crystal Structure: Orthorhombic, typically prismatic crystals, often tabular. Cleavage: Poor in two directions. Specific Gravity: 3.27-3.37. It is idiochromatic, meaning its color comes from its essential chemical composition (iron). Fairly brittle.

Peridot is the gem-quality variety of the mineral olivine. It forms in mafic and ultramafic igneous rocks (such as basalt, peridotite, and dunite) deep within the Earth's mantle and is brought to the surface through volcanic activity. It can also be found in meteorites. The geological age varies significantly, as it forms continuously within the Earth and is brought to the surface periodically.

Primarily used as a gemstone in jewelry (rings, necklaces, earrings, bracelets) due to its attractive green color and moderate hardness. It is typically faceted or cut into cabochons and beads, as seen in the image. Although not common, industrial olivine (non-gem quality) is used as a refractory material, in sandblasting, and as a slag conditioner in metallurgy.

Peridot is one of the few gemstones that occurs in only one color: green. Its intensity and tint depend on the amount of iron in its crystal structure. It is often referred to as 'the evening emerald' for its sparkling green hue, which looks brilliant under artificial light. Some peridot also comes from pallasite meteorites, making it one of two gemstones (the other being diamond) known to form extraterrestrially. Peridot is the birthstone for August.

In the field, peridot is identified by its characteristic olive-green to yellowish-green color, vitreous luster, and its occurrence in volcanic rocks (especially basaltic lavas) or as xenoliths in mantle rocks. When found as loose crystals or pebbles in alluvial deposits, its color and hardness (scratching glass but being scratched by quartz) are key indicators. Major sources include the San Carlos Apache Indian Reservation in Arizona (USA), China, Vietnam, Pakistan, and Myanmar. When identifying beads like those pictured, the color, translucency, and the presence of any natural inclusions visible under magnification can help confirm its identity as peridot, though distinguishing it from other green gemstones or glass would require gemological tools.