agate
Americannoun
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a variegated chalcedony showing curved, colored bands or other markings.
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a playing marble made of this substance, or of glass in imitation of it.
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Printing. a 5½-point type of a size between pearl and nonpareil.
adverb
noun
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an impure microcrystalline form of quartz consisting of a variegated, usually banded chalcedony, used as a gemstone and in making pestles and mortars, burnishers, and polishers. Formula: SiO 2
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a playing marble of this quartz or resembling it
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Also called: ruby. printing (formerly) a size of printer's type approximately equal to 5 1/ 2 point
noun
Usage
What is agate? Agate is a variety of the mineral chalcedony (a type of quartz), specifically one with bands or stripes or other markings. It is often considered a gemstone. It can occur in a wide variety of colors, including white, yellow, red, and black. The key quality of agate is its banding, which is crystal that has formed in the rock. Agate is considered a semiprecious stone, which is a label assigned to some stones that have a lesser value than those considered precious. When used in jewelry, agate is often cut into a shape called a cabochon, which is polished but not cut into facets. When loose (not set in jewelry), they are often sold in the form of a geode or slab. Several forms of chalcedony are considered agates if they contain banding, including the gemstones onyx and sardonyx. Specific kinds of agate are named for their colors and patterns. For example, moss agate features a green pattern that resembles moss. Agate is one of the traditional birthstones for the months of May and June. It is associated with the zodiac sign Gemini. Example: I bought a beautiful yellow agate geode at the rock and crystal shop.
Other Word Forms
- agatelike adjective
- agatoid adjective
Etymology
Origin of agate
1150–1200; Middle English ac ( c ) ate, achate, agaten (compare Dutch agaat, Old Saxon agāt, Old High German agat ), apparently < Old French agathe or Italian agata (initial stress) ≪ Medieval Latin achātēs < Greek achā́tēs
Explanation
Agate is a gemstone that's similar to quartz. Jewelry, including pins and earrings, is sometimes made from agate. Agate is mainly found in volcanic rock, and it's often distinguished by its lines or bands, a result of silicate material layering as it filled in cracks in these ancient rocks. Agate has long been used for carving ornaments and vessels, including beads, marbles, jewelry, mortars, and pestles. The name agate comes from the Greek akhates, the name of a river in Sicily where the stone was commonly found about 3,000 years ago.
Vocabulary lists containing agate
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Joel Otterson’s intimate sculptures set moss agate in silver and brass at Ehrlich Steinberg.
From The Wall Street Journal • Feb. 27, 2026
It’s a desolate alluvial fan on the southern flanks of the Cady Mountains, where sparkling calcite crystals and pieces of quartz, jasper and agate are continually carried down the slopes by thunderstorms and flash floods.
From Los Angeles Times • Jul. 16, 2023
A writer's block crystals gift set available through Etsy offers agate, carnelian, tiger eye, citrine, amethyst and clear quartz crystals to help those struggling to formulate sentences.
From Salon • Oct. 23, 2022
Moss agate, which is slightly harder than opal, has also risen in demand.
From Seattle Times • Oct. 2, 2022
“Not you. I’m fear’d you have some ill plans agate, that bring you about folk’s houses at this time o’ night.
From "Jane Eyre" by Charlotte Brontë
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
