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

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)

It was one with a big moss agate, with the outline of a pine tree on it, and a lot of emeralds and rubies set around its center.

From Jack Ranger's Western Trip Or, from Boarding School to Ranch and Range by Young, Clarence

Specimens from Willamette River, Oregon, of these beautiful productions; jasper, moss agate, obsidian, etc., rare.

From American Antiquities Auction Catalogue, January 8, 1898 by Norman, Wm. B.