Peridot and Citrine Gemstones (in a ring setting)

Peridot (green gem): Hardness 6.5-7 on Mohs scale, typically olive green, vitreous luster, orthorhombic crystal system, rather brittle with conchoidal fracture. Specific gravity 3.2-4.3. Citrine (yellow gem): Hardness 7 on Mohs scale, colors range from pale yellow to brownish-orange, vitreous luster, trigonal crystal system, no cleavage (conchoidal fracture). Specific gravity 2.65.

Peridot: Forms in mafic and ultramafic igneous rocks, such as basalt and peridotite, often brought to the Earth's surface by volcanic activity. It is also found in meteorites. Geological age varies greatly, but many deposits are associated with Cenozoic volcanic activity. Citrine: Is a variety of quartz, which forms in igneous, metamorphic, and sedimentary environments. Most natural citrine forms from amethyst or smoky quartz exposed to high temperatures, often associated with granitic pegmatites. It can also be artificially heat-treated amethyst. Geological age is highly variable depending on the quartz formation.

Both Peridot and Citrine are primarily used as gemstones in jewelry due to their attractive colors and relative hardness. They are cut into various shapes for rings, necklaces, earrings, and bracelets. Peridot is sometimes collected as mineral specimens, particularly larger crystals. Citrine is also popular in ornamental carvings and decorative items.

Peridot is one of the few gemstones that occurs in only one color, varying only in its intensity and tint of green. It's often associated with Hawaii, where small peridot crystals can be found in volcanic beach sand. Citrine's name comes from the Old French word 'citrin', meaning 'lemon'. It is sometimes called 'light topaz', but this is a misnomer as it is distinct from topaz. Brazil is a major producer of natural citrine.

To identify Peridot: Look for its distinct olive-green color, often with a slightly yellowish tint. It typically has a good luster. In rough form, it's often found as small, rounded crystals in volcanic rocks. To identify Citrine: Its color ranges from yellow to brownish-orange, and it will scratch glass. Natural citrine tends to have a more pale and even color distribution compared to heat-treated amethyst, which might have orange or reddish tints and often a 'sugar-frosted' appearance. Both are typically found in gem gravels or within their host rocks (volcanic for peridot, pegmatites/hydrothermal veins for citrine). For collectors, larger, well-formed crystals with good color and clarity are most desirable.