sedimentary
Dendritic Chert
Silicon Dioxide with Manganese Oxide Inclusions (SiO2 + MnO2)
Hardness of 6.5-7 on the Mohs scale, microcrystalline texture, yellowish-brown/mustard base color with fine black branching dendritic inclusions, dull to waxy luster, conchoidal fracture.
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Physical properties
Hardness of 6.5-7 on the Mohs scale, microcrystalline texture, yellowish-brown/mustard base color with fine black branching dendritic inclusions, dull to waxy luster, conchoidal fracture.
Formation & geological history
Formed as a chemical sedimentary rock through the accumulation and crystallization of microcrystalline silica in aquatic environments. Black tree-like patterns (dendrites) formed when manganese or iron oxide-rich solutions seeped through micro-cracks.
Uses & applications
Used primarily in lapidary arts for cabochons, tumbled gemstones, decorative pebbles, and educational or collection specimens.
Geological facts
The term 'dendrite' comes from the Greek word 'dendron', meaning tree. Although these black markings look remarkably like fossilized plants or moss, they are purely inorganic mineral growth.
Field identification & locations
Identified by its hard, dense crypto-crystalline quartz body that scratches glass, paired with distinct dark fern-like patterns. Common in riverbeds, gravel deposits, and sedimentary formations worldwide.
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