Green Moss Agate Tumbled Gemstone

Moss Agate forms when silica-rich water seeps into cavities and fractures in volcanic rock and slowly hardens into chalcedony, a compact form of quartz. As it sets, traces of iron and manganese — and sometimes green chlorite or hornblende — crystallize inside the stone in branching, plant-like patterns. Despite its name and the foliage it appears to hold, no plant is ever present; the moss is pure mineral. Judy Hall records it as a common stone found in the United States, Australia, and India, with further deposits in Brazil and Uruguay.

Moss Agate is a translucent-to-opaque variety of chalcedony, a cryptocrystalline form of quartz with the chemical formula SiO₂. Unlike banded agate it shows no concentric bands; instead its green, brown, or reddish dendrites are inclusions of iron and manganese oxides or minerals such as chlorite and hornblende. It measures 6.5 to 7 on the Mohs scale and belongs to the trigonal crystal system, with a waxy to vitreous luster.

Roman naturalists wrote that agate worn against the skin made a person more agreeable and eloquent and could turn away a coming storm — a reputation Moss Agate carried into the fields and marketplaces of the ancient world., Moss Agate became known as the gardener's stone: growers traditionally hung it on plows, tools, and the horns of oxen, trusting its mossy figures to promise a rich harvest and healthy crops., and Its old trade name, 'Mocha stone,' comes from the port of Mocha in Yemen, through which these dendritic stones were shipped to Europe, where 18th-century collectors prized the tiny landscapes sealed inside them.