Crystal cabinet
Peridot
Olivine, specifically a magnesium-iron silicate in the forsterite to fayalite series, gem-quality pieces being toward the magnesium-rich, iron-bearing forsterite end.
Peridot is a yellow-green to olive transparent stone, glassy, and the color comes from iron in the olivine, so it should look green even in decent daylight rather than only under a shop spotlight. Good pieces are clear; many are slightly sleepy or veiled. It does not show emerald's blue-green in the classic Colombian sense, and it does not have jade's opacity; bottly, bubbly green is glass.
What it actually is
| Name used here | Peridot |
| Mineral or material | Olivine, specifically a magnesium-iron silicate in the forsterite to fayalite series, gem-quality pieces being toward the magnesium-rich, iron-bearing forsterite end. |
| Hardness | About Mohs 6.5 to 7. |
| How it forms | Olivine is a major mineral of the Earth's mantle and of many basalts. Gem peridot comes from mantle xenoliths, from volcanic bombs, and from altered ultramafic rocks, famously the island of Zabargad in the Red Sea and, in the modern trade, from Arizona, Pakistan, Myanmar, and China; the green is iron, not a stored leaf. |
Trade names and mix-ups
Peridot, chrysolite, and evening emerald are names that have slid around green stones for centuries, and in antiquity topaz often meant this olivine rather than the mineral now called topaz. It is not emerald, though some historic treasury emeralds have turned out to be peridot, and glass imitates the color. A murky olive pebble is not a Red Sea relic because a pamphlet said Egypt.
Care
Hard enough for jewelry and still easy to scuff, and olivine is sensitive to acids and to sudden heat. Do not soak it in vinegar, lemon, or cleaning baths, do not steam it, and do not leave it on a hot sill or in a sauna. Salt storage is a scratch-and-damp idea with no benefit. Wipe with a soft damp cloth and dry. Perfume is a poor neighbor. Dust on the facets should be rinsed away lightly rather than ground in, then dried at once, and the rinse goes down the sink, not into a cup.
Provenance
Modern peridot comes from places that include the San Carlos Apache Reservation in Arizona, Pakistan, Myanmar, and China, each with its own labor and land politics; a tumbled chip does not carry the island of Zabargad with it just because Pliny's topaz was probably this mineral. Buy modestly, ask the country if the seller is using Egypt or a mine name as romance, and do not fund a curse-of-the-pharaohs markup on an olivine.
Symbolism
- a check in daylight
- green from iron
- an island in an old book
- impressions corrected at noon
Folklore, only where it exists
Zabargad, also called Topazios and later St. John's Island, supplied green olivine to the Mediterranean world in Hellenistic and Roman times, and modern gemology generally reads Pliny's topazos as peridot rather than as the mineral we now call topaz. Some famous green stones in European treasuries, long called emerald, have been reidentified as peridot, which is a good lesson in names. Medieval and early modern writers assigned the usual protective and night-related virtues to a stone that is actually at its best in daylight, because the color goes muddy in dim rooms. Contemporary lists add prosperity and emotional balance. The Wilde Altar uses the daylight fact. Take the stone to a window or a door at noon and see whether the green you remember from the kitchen bulb is still the green in the sun. Correct the impression. Iron in olivine does not care about your mood, and it will not guard you. Looking twice is the whole power on offer.
Cautions
An original practice
The Noon Comparison
- A piece of peridot
- A kitchen or hallway with artificial light
- A door or window at midday
- A notecard and a pen
- 1Under the indoor light, write three words for the color you think you see.
- 2Step outside or to the daylight door. Hold the stone in the shade of your hand, not in a hot beam on a sill, and look again.
- 3Write three new words. If they differ, that is the result. You do not need them to be poetic.
- 4If you are with someone, a partner or a housemate of any gender, you may trade cards. Their eyes are allowed to disagree. Nobody wins the mineral.
- 5Bring the stone back in, wipe it if your hands were sunscreened, dry it, and put it away from the vinegar.
The bulb is not the sun. I can change my mind when the light changes. Iron green does not need my loyalty, only my accuracy.
Store peridot in a cloth, not in a jumble of harder grit, and not in a glove box that becomes an oven. The card can go in the journal.
A practical action. If the daylight correction reminds you of a decision you made under bad information, revisit the decision today with the better light and a phone call if one is required.
Substitutions
- A green glass bottle shard, handled as glass and labeled glass
- A sprig of a living herb you already cook with, looked at indoors and outdoors, then eaten or composted as food and not as peridot
Beginner questions
- Is peridot the same as emerald? No. Emerald is beryl. Peridot is olivine. They can both be green, and museums have mixed them up, which is an argument for expertise, not for treating them alike at home.
- Is it the same as modern topaz? No. Ancient topaz was often this stone. Modern topaz is a different mineral. The words moved; the chemistries did not.
- Can I clean it with vinegar or drink a sour peridot water? No. Acids attack olivine, and elixirs are refused here entirely. Use a soft damp cloth and dry it.