Crystal: An Ordered Solid, and a Word for Perfect Clarity
A crystal is a solid whose atoms are arranged in a regular repeating pattern. The word also means fine cut glass, and clear as crystal is one of the oldest similes in English.
A crystal is a solid in which the atoms sit in a repeating three-dimensional pattern. That internal order is what produces the flat faces and sharp angles you can see: the shape of a crystal is a visible consequence of an invisible arrangement.
- An ordered solid. *A quartz crystal.*
- Fine cut glass. *A set of crystal glasses.*
- Perfectly clear (adjective). *Crystal clear water.*
- A timing component. *A quartz crystal oscillator.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | crystal | A salt crystal. |
| Adjective | crystalline | A crystalline structure. |
| Verb | crystallise | The solution crystallised. |
| Noun | crystallography | X-ray crystallography. |
| Compound | crystal clear | Crystal clear instructions. |
How it is used in a sentence
- Snowflakes are ice crystals.Six-fold symmetry comes from the water molecule's shape.
- His thoughts crystallised over the weekend.Became definite — a very common figurative use.
- Let me be crystal clear.A politician's favourite preface.
Where crystals matter
- Geology — mineral identification depends on crystal form
- Chemistry — X-ray crystallography revealed the structure of DNA
- Electronics — quartz crystals keep watches and computers on time
- Cooking — sugar and salt are crystals, and controlling their size changes texture
- Glass is not a crystal at all: its atoms have no repeating order
From Greek *krystallos*, ice, from *kryos*, frost. The Greeks believed rock crystal was water frozen so hard it could never melt, which is why the word for ice ended up naming a mineral.
Is crystal glass really crystal?
No. Lead crystal is a glass, and glass has no ordered atomic structure. The name refers to its clarity and sparkle.
What does crystallise mean figuratively?
To become clear and definite — used of plans, ideas and opinions that were previously vague.