Tree agate is a synonym for Moss agate. This type of chalcedony (chalcedony is a microcrystalline variety of quartz, agates falls under this category) consists of tubular, inclusions and branching, filamentous growths within the stone which resembles moss. This stone contains iron minerals giving moss agates shades of red, brown, yellow, black, and green.
Moss agates do not have the concentric banding that agates are commonly associated with. Moss agates can appear messy like overgrown vines. Some moss agates may contain concentric banding in small areas and also have the moss-like inclusions. However, mostly all moss agate does not contain the concentric banding of agates. But, because moss agates are mainly made of chalcedony, they are considered an agate.
One of the best theories available today regarding Moss agate formations was hypothesized by Raphael Liesegang. The theory is that Moss agate formation is a series of chemical reactions between ferrous sulfate (iron and sulfur) and sodium silicate combined with high pressures. These chemical reactions produce a “channeling” effect throughout the molten mass of silica leaving a trail of tubular structures within the rock.
The beauty of moss agates are only seen when the stone has been cut and polished. These stones are very common and used for jewelry making and carvings.
A variety of Agate, Plume agate has fluffy or mossy inclusions which often appear to be soft and have depth. Sometimes plume agate inclusions resemble feathers, plants, or flowers. They are filament growths of mineral inclusions that resemble ferns or feathers usually composed of iron or manganese oxides. The stone itself is a variety of moss agate with blooms of black inclusions. Black plume agate is commonly found in Texas, California, and Oregon. The These black plume agate beads are white and black to bluish-black.
Plume agate is a variety of moss agate
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