agate

American  

[ag-it] / ˈæg ɪt /

noun

1. a variegated chalcedony showing curved, colored bands or other markings.

2. a playing marble made of this substance, or of glass in imitation of it.

3. Printing. a 5½-point type of a size between pearl and nonpareil.

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Agate ¹ British  

/ ˈæɡeɪt /

noun

1. James ( Evershed ). 1877–1947, British theatre critic; drama critic for The Sunday Times (1923–47) and author of a nine-volume diary Ego (1935–49)

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agate ² British  

/ ˈæɡɪt /

noun

1. 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

2. a playing marble of this quartz or resembling it

3. Also called: ruby.  printing (formerly) a size of printer's type approximately equal to 5 1/ 2 point

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agate ³ British  

/ əˈɡeɪt /

adverb

1. dialect on the way

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agate Scientific  

/ ăg′ĭt /

1. A type of very fine-grained quartz found in various colors that are arranged in bands or in cloudy patterns. The bands form when water rich with silica enters empty spaces in rock, after which the silica comes out of solution and forms crystals, gradually filling the spaces from the outside inward. The different colors are the result of various impurities in the water.

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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

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

Adjacent to the entombed Griffin Warrior’s wrist was a carved and gold-tipped agate, almond-shaped and just 1.3 inches in length, here making its public debut outside Europe.

From Los Angeles Times • Sep. 10, 2025

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

Boma Jewelry Treasured Agate Pendant Necklace: Designed in Seattle, this agate disc stands for courage and new beginnings.

From Seattle Times • Nov. 14, 2021

Kaori opened her empty hand as if the agate would magically appear there.

From "Hello, Universe" by Erin Entrada Kelly

Related Words

• font