opal

¹

[oh-puhl]

noun

1. a mineral, an amorphous form of silica, SiO 2 with some water of hydration, found in many varieties and colors, including a form that is milky white.

2. an iridescent variety of this that is used as a gem.

3. a gem of this.

Opal

²

[oh-puhl]

noun

1. a female given name.

opal

/ ˈəʊpəl /

noun

1. an amorphous, usually iridescent, mineral that can be of almost any colour, found in igneous rocks and around hot springs. It is used as a gemstone. Composition: hydrated silica. Formula: SiO 2 . n H 2 O

opal

1. A usually transparent mineral consisting of hydrous silica. Opal can occur in almost any color, but it is often pinkish white with a milky or pearly appearance. It typically forms within cracks in igneous rocks, in limestones, and in mineral veins. It also occurs in the silica-rich shells of certain marine organisms. Chemical formula: SiO ₂ ·nH ₂ O.

Other Word Forms

• opal-like adjective

Word History and Origins

Origin of opal¹

1350–1400; Middle English < Latin opalus < Greek opállios opal, gem; probably from a source akin to Sanskrit upala precious stone

Word History and Origins

Origin of opal¹

C16: from Latin opalus, from Greek opallios, from Sanskrit upala precious stone

Example Sentences

Her opal blue eyes light up as she rhapsodises about her "British princess".

From BBC

The fossils were found by Elizabeth Smith and her daughter Clytie of the Australian Opal Centre in Lightning Ridge, who have spent decades working and searching over the opal fields.

From Science Daily

Fossilised pieces of the animal's jaw bone were found in opal fields in northern New South Wales, alongside evidence of several other ancient and now extinct monotreme species.

From BBC

S. dotyi’s microspheres, in contrast, remained uniform, arranging themselves in an orderly, crystalline lattice like that found in an opal—perfect for reflecting and amplifying certain colors.

From Science Magazine

“Limbo” also is built around a man looking for answers, in this case about the 20-year-old disappearance of an Indigenous schoolgirl in the titular town, a remote, depressed opal mining outpost.

From Los Angeles Times

When To Use

What does opal mean?

An opal is a gemstone that’s best known for its iridescent, milky-white variety.Other varieties are black and gray, but it can be almost any color. As a mineral, opal is a form of silica.Unlike many of the other gemstones used in jewelry, opal is not crystalline, meaning it does not form in a crystal structure—it looks like a stone, as opposed to a faceted jewel like a diamond.Opal gemstones are classified as common or precious. Precious is a label given to certain gemstones that are high in value. Opals labeled precious are typically those that display a high level of iridescence.Opal is the traditional birthstone for the month of October. It is associated with the zodiac signs Libra and Scorpio.Example: The opal pendant had flecks of green, pink, and blue.