7.8" Polished Agate and Amethyst Geode "Egg" - Madagascar

This is a beautiful 7.8" tall polished egg, made from a banded agate and quartz encrusted geode. This mineral egg was mined, shaped and hand polished in Madagascar. The banded agate displays a variety of colors ranging from white to red and the cavity within this geode is lined with quartz crystals. The quartz within the cavity appears to have some purple coloration, however not enough to confidently consider it to be amethyst. The yellow coloration of the quartz around the exterior of the egg can likely be attributed to iron oxidation.

Comes with the pictured display stand.

Agate is a variety of microcrystalline quartz (chalcedony) that displays translucence and, in some cases, banding. Agate primarily forms when silica-rich fluids fill pockets within rocks and/or fossils, depositing the silica along the walls of the rock. This process can result in banding patterns, as the compositions and impurities of these depositing fluids change over time. These banding patterns can either form as flat layers, creating linear patterns known as waterline agate, or as rounded layers, forming more common ring-like patterns. These patterns depend on the surfaces available for deposition.

Quartz is the name given to silicon dioxide (SiO2) and is the second most abundant mineral in the Earth's crust. Quartz crystals generally grow in silica-rich environments--usually igneous rocks or hydrothermal environments like geothermal waters--at temperatures between 100°C and 450°C, and usually under very high pressure. In either case, crystals will precipitate as temperatures cool, just as ice gradually forms when water freezes. Quartz veins are formed when open fissures are filled with hot water during the closing stages of mountain formation: these veins can be hundreds of millions of years old.
Chalcedony var. Agate & Quartz
7.8 x 5.8"