Prehnite does not shout. It is a pale, slightly milky green, sometimes leaning yellow or even near-white, with a glassy to pearly luster. People who know it love it; people who have not met it usually ask whether it is jade or green amethyst. It is neither. It is its own mineral, calcium aluminum silicate hydroxide, and it has been cut and set in fine jewelry since it was first described in 1788, named for the Dutch colonial governor who sent samples home.
Where prehnite comes from
South Africa supplies the bulk of the translucent gem material, with China, Namibia, and the United States (New Jersey, historically) producing smaller amounts. Prehnite usually forms as botryoidal or stalactitic growths in volcanic basalt vesicles, which is why it is most often cut en cabochon. The best material shows a translucent, almost watery body with a uniform apple-green color. Some rough contains inclusions of epidote, which darken parts of the stone and are usually cut around.
Color and clarity
Prehnite's color range is narrow on purpose. The sweet spot is a light, even, slightly desaturated green, sometimes described as "mint" or "wine bottle glass." Yellowish prehnite is cheaper; gray or brown material is usually industrial. Translucency matters more than color: a stone you can read a newspaper through when held up to a light is premium. Fully opaque prehnite is still pretty, but it reads as a craft stone rather than a gem.
A small number of prehnite specimens contain internal crystallites that give a soft chatoyant "cat's eye" band. These are rare and usually cut as cabochons to show the line across the dome.
Durability at the bench
Prehnite lands at 6 to 6.5 on the Mohs scale. It is brittle, and it has a tendency to chip at the girdle if the setter over-tightens a bezel. We cut prehnite cabs with a slightly thicker girdle than we would for a quartz, and we seat them on a thin heat-pool of hard wax before we close the bezel so the stone sits flat and does not rock. For rings, we recommend it for evening wear; for pendants and earrings, it is an everyday stalwart.
Treatments
Prehnite is typically untreated. It is not commonly dyed, irradiated, or fracture-filled, which is refreshing in a market full of altered green stones. Some material is oiled or waxed to improve surface luster, but that wears off over years of wear and does not affect value in any serious way. If you are comparing prehnite to chrysoprase, prehnite is the softer, more translucent of the two.
How to wear it
Prehnite works in both warm and cool metal settings. In yellow gold it reads almost vintage, like something pulled from a Victorian estate case. In platinum or white gold it reads modern and architectural. We have set prehnite as a large oval on a simple silver chain, as a round cab in a halo of small diamonds, and as a pair of drop earrings on shepherd hooks. Because the color is so light, it layers well with other soft stones — rose quartz, amazonite, pale aquamarine — without competing.
Cleaning and care
Warm water, a drop of dish soap, and a soft brush. Skip the ultrasonic. The vibrations do not usually crack prehnite, but over years they can loosen a polished surface and bring out the stone's natural brittleness at the girdle. Skip the steam too. Keep it away from household bleach, which will discolor the green to a dull gray. Put prehnite jewelry on after you have applied perfume and hairspray, and take it off before washing dishes or hitting the gym. Our general guide to chemical exposure has the full list of household products that quietly damage gemstones.
A word on imitations
Because prehnite is not a household name, it gets imitated more often than you would expect. Green glass and pale green dyed chalcedony both turn up in budget listings labeled prehnite. Real prehnite has a slightly waxy, almost greasy luster that glass cannot quite reproduce, and it often shows faint fibrous structure when viewed through a loupe. If a deal looks too good for the color, ask for a video of the stone rotating. A glass fake will flash a flat, uniform color; real prehnite shifts subtly as it turns.
Why we like setting it
Prehnite takes a high polish and sits beautifully in brushed yellow gold. It reads as expensive without costing it, and it works for both men's signets and women's stackable bands. We have set it beside small diamonds for a quiet contrast, and alone as a large oval on a heavy silver chain. Because the color is so soft, it does not fight with clothing colors the way a saturated emerald will. It is the green you reach for when you want green that behaves.
Rhodium plating, which gives white gold jewellery its bright finish, is covered in the Wikipedia article on rhodium.
Frequently Asked Questions
How do I verify a factory before placing a bulk order?
Request a production video, business license, export records and a paid sample run. A factory that accepts a 50-piece test order is usually a real manufacturer.
What payment terms do you offer?
30% T/T deposit with the balance against the bill of lading. This protects both sides on first orders and can move to net terms after a track record.
What is your normal reject rate?
3–5% under 10x loupe inspection for cast and set pieces. Defective units are replaced free in the next shipment.
Where is the factory located?
Wuzhou, Guangxi, China—the core lab-grown and moissanite manufacturing cluster. Shipments go via Guangzhou or Shenzhen ports.
