metamorphic
Polished Jasper / Gneiss (Metamorphic/Siliceous Egg)
Siliceous Gneiss / Banded Metamorphic Rock
AI-generated identification · may be incorrectHardness 6.5-7 on Mohs scale; vitreous to polished luster; multicolored with bands of dark grey/black, golden-brown, ochre, and green-grey; foliated/banded metamorphic texture composed largely of quartz, feldspar, and amphibole/mica; specific gravity ~2.6-2.8.
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Physical properties
Hardness 6.5-7 on Mohs scale; vitreous to polished luster; multicolored with bands of dark grey/black, golden-brown, ochre, and green-grey; foliated/banded metamorphic texture composed largely of quartz, feldspar, and amphibole/mica; specific gravity ~2.6-2.8.
Formation & geological history
Formed through high-grade regional metamorphism of igneous or sedimentary protoliths subjected to directional tectonic pressures and heat, resulting in mineral segregation into dark and light bands.
Uses & applications
Popular in ornamental carvings, lapidary art, polished decorative eggs, spheres, paperweights, and metaphysical collector items.
Geological facts
Egg-shaped carvings from banded stones date back centuries and are popular in lapidary art to showcase the natural flow of foliated mineral banding around a curved three-dimensional surface.
Field identification & locations
Recognized by its distinct compositional layering (gneissic foliation or banded jasper/flint patterning) visible seamlessly around the polished surface. Frequently carved and produced in regions like Madagascar, India, or Brazil.
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