This milky chalcedony is a unique member of the agate family which has grown a branching pattern of manganese oxide across the stone. These dark feathers are called dendrites, an inorganic phenomenon that makes this piece a rare find.

As the manganese cools, it crystalizes into thin, tree-like shapes. Unlike an organic plant fossil, a dendrite’s “branches” do not overlap. dendrites appear in many other forms throughout nature, such as the fractal pattern of a snowflake.

The dark branching patterns upon the cloudy agate of this pendant are a beautiful example of geochemistry.

This pendant is crafted with a polished dendritic agate and set into a sterling silver bezel backing. All additional components of the necklace are also sterling silver, including an 18" (45cm) chain.

The necklace comes with a handsome display/storage box and a small information card that also serves as the certificate of authenticity. These pendants have been photographed individually by size and you can see all the currently available dendritic agate pieces in the collection below.

Dendritic agates are a type of gemstone that has been infused with fracturing bands of manganese oxide, producing branches of crystalized material that crisscross the crystal matrix.

The base agate is a silicate with a cryptocrystalline structure, meaning the crystals can only be revealed under microscopic observation. They form in a variety of environments, both in acidic and basic volcanic materials and in sedimentary environments near the Earth’s surface. Often these agates will feature bands of different color which appear to flow into one another, such as the blacks and whites of these pendants.

Agates are beautiful and come in many shapes and sizes. The dendrites in these particular gemstones make them stand out as unique. Dendrites are a recurring motif across the natural world, their branching patterns appearing in our brains' firing neurons, snowflakes falling from the sky, and geologic formations like these agates.

Crystal dendrites form when the superheated agate and iron or manganese oxide mix. The manganese then crystallizes well below its solidification point, due to a process called supercooling.

The process occurs quite quickly and can cause the crystals to split off and grow outwards in thin branching patterns. Over time, the manganese deposits in the agate expand, until they become visible fractals on the stone's surface.

These dendritic agates form across the world, particularly in Brazil, India, and Turkey. Their ubiquity and appearance led early paleontologists to believe dendrites’ plant-like appearance was organic. We now know the process is entirely geologic and can be categorized as "pseudofossils."

An expert can tell an inorganic dendrite and fossil plant apart at a glance, but a good rule of thumb is to see if any of the "branches" overlap with one another. A fossil plant may have fallen into the mud and twisted over itself, whereas a dendrite grows horizontally and rarely intersects. Dendrites also form along one side of a rock, not branching out from a single stem.

The dendrites’ tree-like appearance has associated the stones with ideas of renewal and connection to nature, but the stones are simply a beautiful expression of the natural world all their own. These pieces are a demonstration of a fascinating geochemical process, the intermingling of two minerals to produce a new gemstone.