moonstone

American  

[moon-stohn] / ˈmunˌstoʊn /

noun

1. Also called precious moonstone.  a semitransparent or translucent, opalescent, pearly-blue variety of adularia, used as a gem.

2. any of several adularescent feldspars, as certain varieties of albite, labradorite, or oligoclase, used as gems.

3. (not used technically) any milky or girasol stone used as a gem.

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moonstone British  

/ ˈmuːnˌstəʊn /

noun

1. a gem variety of orthoclase or albite that is white and translucent with bluish reflections

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Usage

What is moonstone? Moonstone is a variety of gemstone that’s commonly milky white with a blue, silver, or multicolored iridescent tint. It is a variety of the mineral feldspar (more specifically, adularia or orthoclase). Moonstones can be transparent or semitransparent. More transparent moonstones are typically more valuable and higher in price. The moonstone is one of the birthstones for the month of June, along with pearl and alexandrite. It’s associated with the zodiac signs Gemini and Cancer. The word moonstone is also sometimes used to refer to other varieties of feldspar, or, less technically, to any milky-colored gemstone. Example: I have a moonstone ring that gives off a blue shine when it catches the light.

Etymology

Origin of moonstone

First recorded in 1625–35; moon + stone

Example Sentences

I don't know if you remember, but at the end you give her a moonstone.

From Salon • Jun. 11, 2023

Prayer bead bracelets are strung with smooth Australian opal, moonstone or bone.

From Los Angeles Times • Nov. 29, 2018

While we discuss our various adventures in the pen trade, we nosh on raw moonstone oysters from Rhode Island, an absolute palate-seducer.

From Washington Times • Jan. 7, 2016

But I wear a small moonstone on my hand, the symbol of hope.

From New York Times • Mar. 13, 2014

Then he puts a finger to my moonstone badge and says, “By the power vested in me as a training agent, I promote you, Amari Peters, to Junior Agent.”

From "Amari and the Night Brothers" by B.B. Alston