Green Agate

Green agate is a banded chalcedony (cryptocrystalline quartz) showing green coloration. Natural green agate is relatively uncommon; the deep, uniform emerald-green slices widely sold for jewelry and craft are usually common gray agate that has been dyed.

Genuine natural green coloring in chalcedony comes from chromium or nickel-bearing inclusions, as in chrome chalcedony (mtorolite) and green moss agate, where the green appears as patchy or dendritic inclusions rather than even color.

Green agate is valued for its calming color, durability and affordability, and is one of the most common agate colors offered in bead and slice form.

Agate forms when silica-rich groundwater deposits successive layers of chalcedony inside cavities in volcanic rock. The banding records repeated deposition episodes.

Natural green color arises when chromium- or nickel-bearing minerals are incorporated during or after deposition. In chrome chalcedony, traces of chromium tint the silica green; in moss agate, green chlorite or hornblende inclusions create the mossy appearance.

Much commercial green agate, however, is gray banded agate (often from Brazil) that is artificially dyed by soaking porous bands in colored solutions, producing an even, intense green not seen in nature.

Even, intense, uniform green throughout a banded slice usually indicates dye; natural green tends to be paler, patchy, or confined to inclusions and dendrites. Hardness is 6.5-7 (scratches glass), luster waxy to vitreous, streak white, and edges are translucent.

Natural chrome chalcedony shows a soft, slightly cloudy green; moss agate shows green inclusions suspended in clear-to-white chalcedony.

Look-alikes include green aventurine (granular quartzite, more opaque with sparkly mica), chrysoprase (apple-green chalcedony, usually more uniform and translucent), and dyed agate. A telltale sign of dye is unnaturally vivid color pooling along porous bands.

Green agate is widely cut into cabochons, beads, slices, coasters and decorative slabs. Its hardness and toughness make it suitable for pendants, bracelets and rings, and dyed material provides an inexpensive, colorful option for craft jewelry.

Natural chrome chalcedony and fine green moss agate are more collectible and used in higher-end lapidary work.

Metaphysically, green agate is associated with growth, balance, abundance and emotional healing; these are spiritual traditions rather than proven properties.