moss agate

American  

noun

1. a kind of agate or chalcedony containing brown or black mosslike dendritic markings from various impurities.

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moss agate British  

noun

1. a variety of chalcedony with dark greenish mossy markings, used as a gemstone

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Etymology

Origin of moss agate

First recorded in 1790–1800

Example Sentences

Joel Otterson’s intimate sculptures set moss agate in silver and brass at Ehrlich Steinberg.

From The Wall Street Journal • Feb. 27, 2026

Citrine, aventurine and moss agate are said to attract abundance.

From Los Angeles Times • Mar. 31, 2018

If you take a pen and drop some ink into a tumbler of water, it will scatter and form for the moment an appearance like a moss agate.

From Three Years on the Plains Observations of Indians, 1867-1870 by Tuttle, Edmund B.

I apologized to Joe for seeming to have aided and abetted "Lefty" in trying to get away with the moss agate, and Joe apologized to me for that warning about the Yellowstone.

From Down the Yellowstone by Freeman, Lewis R. (Lewis Ransome)

The shell contained a piece of clear quartz crystal, and the bowl a moss agate.

From The North American Indian by Curtis, Edward S.