Overgrown

Like something you'd find if you cracked open a piece of sea glass and found a forest inside.

The prehnite is pale and translucent — a soft, watery green that catches light like frosted glass. And then the black tourmaline needles cut through it. Sharp, dark, and deliberate-looking, even though nothing about this stone was planned by human hands. It just grew that way. Over millions of years, tourmaline crystals formed inside the prehnite as it cooled, leaving behind these thin dark threads suspended in green.

It's one of the more visually striking combinations in the mineral world, and it looks even better in person. Every bead is different. Every bead has its own map.

Part of Unearthed — a collection of natural gemstone bracelets, each stone chosen for what it looks like straight out of the earth.

THE STONE

Prehnite calcium aluminum silicate / translucent / pale green

Prehnite is a calcium aluminum silicate mineral first described in the late 1700s and named after Colonel Hendrik von Prehn, who brought specimens from South Africa to Europe. It forms in igneous and metamorphic rock, often in association with zeolites and other silicate minerals. Its most distinctive quality is its translucency — light passes through it in a way that few stones allow, giving it that characteristic glassy, almost liquid appearance. Natural prehnite ranges from pale yellow-green to a deeper olive, and its clarity varies widely from specimen to specimen. It has been found in South Africa, Australia, China, and the United States.

Black Tourmaline schorl / boron silicate / natural inclusions

The dark needles running through these beads are black tourmaline — specifically the variety known as schorl, the most common form of tourmaline in nature. When prehnite forms around existing tourmaline crystals, or when tourmaline grows within a prehnite matrix, the result is this dramatic combination: dark, needle-like crystals suspended inside translucent green. It's a completely natural occurrence, and no two beads will ever look exactly alike. Black tourmaline has historically been associated with protection and grounding — a fitting counterpart to prehnite's quiet, open quality.

CARE INSTRUCTIONS

Prehnite is relatively durable but should be handled with some care — avoid dropping it on hard surfaces, as the translucent structure can be more susceptible to chipping than denser stones. Keep away from prolonged water exposure and remove before swimming, showering, or soaking. Avoid harsh chemicals, perfumes, and lotions. Wipe clean with a soft dry cloth. Store flat or in a pouch to protect both the stone and the stretch cord.