Peridot: one color, worn well

Peridot is the gem-quality form of olivine, a common rock-forming mineral, which makes it one of the few gemstones formed in the earth's mantle rather than the crust. Some material has even been recovered from meteorites, though most jewelry-grade peridot is mined conventionally.

At 6.5 to 7 on the Mohs scale it is softer than quartz-family stones and considerably softer than sapphire or topaz, which places it firmly in the category of a stone to wear with some care rather than treat as indestructible.

Peridot's green comes from iron built into the crystal structure itself, not from a trace impurity the way chromium colors emerald. That is why the stone has one color family rather than a spectrum: it runs from a bright yellowish lime green through a rich olive to a deeper bottle green, and tone and saturation, rather than hue, are what separate an ordinary stone from a fine one.

The most prized material shows a pure, vivid green with minimal brown or yellow secondary tone. Because color is intrinsic to the crystal rather than added afterward, there is no equivalent of heat treatment for peridot the way there is for sapphire or topaz.

Good peridot is usually reasonably clean to the eye, though it commonly contains small dark crystal inclusions, sometimes called lily pads for their rounded, disc-like shape, along with fine internal fractures. Heavily included material looks cloudy and is worth less.

Peridot is essentially untreated in the trade. Aside from standard cutting and polishing there is no widespread heat, irradiation or fracture-filling practice associated with it, which makes it one of the simpler stones to buy with confidence once its natural clarity is assessed.

Peridot is more vulnerable than the other stones on this list to both mechanical and thermal stress. Sudden temperature change, such as moving from a warm hand into cold water, can cause internal fractures to grow, and a jeweler's torch applied carelessly near a mounted stone can crack it outright.

Household chemicals, including some acids and sulfuric compounds, can also etch the surface over time, so keep peridot jewelry away from cleaning products and put rings on after applying lotion or perfume rather than before. We do not recommend ultrasonic or steam cleaning; a soft brush with lukewarm soapy water is the safer routine.

Peridot has a long history of use that predates most of the periods we sell, and it turns up steadily through Georgian, Victorian and Edwardian jewelry as a bright, affordable green accent, often set alongside seed pearls or diamonds in closed-back gold settings.

It saw a further wave of popularity in mid-century and 1970s jewelry, prized simply for its clean, sunny green, and it remains a comfortable, wearable stone across styles rather than one tied tightly to a single design language.