: a usually amorphous mineral that is a hydrated silica softer and less dense than quartz and typically with definite and often marked iridescent play of colors and is used especially as a gem
Examples of opal in a Sentence
Recent Examples on the Web
There is a close chemical connection to an opal, and the general color and the manner of light reflection are much the same.
—
Mark Fischetti, Scientific American, 15 Oct. 2024
October birthstone October has two birthstones: opal and tourmaline.
—Olivia Munson, USA TODAY, 1 Oct. 2024
Do not use Windex on softer gems like pearls, opals, or emeralds, because the ammonia may damage them.
—Melissa Locker, Southern Living, 4 Oct. 2024
Rough opals appear white, but once polished, their surface shines a rainbow kaleidoscope.
—Olivia Munson, USA TODAY, 1 Oct. 2024
See all Example Sentences for opal 
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Mark Fischetti, Scientific American, 15 Oct. 2024
October birthstone October has two birthstones: opal and tourmaline.
—Olivia Munson, USA TODAY, 1 Oct. 2024
Do not use Windex on softer gems like pearls, opals, or emeralds, because the ammonia may damage them.
—Melissa Locker, Southern Living, 4 Oct. 2024
Rough opals appear white, but once polished, their surface shines a rainbow kaleidoscope.
—Olivia Munson, USA TODAY, 1 Oct. 2024
See all Example Sentences for opal
Dictionary Entries Near opal
Cite this Entry
“Opal.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/opal. Accessed 28 Nov. 2024.
Copy CitationKids Definition
opal
noun
: a mineral with changeable colors that is used as a gem
Love words? Need even more definitions?
Merriam-Webster unabridged
Share