Definition

Adjective: 1. Lacking a definite crystalline structure: Describes a solid substance whose atoms or molecules are not arranged in a regular, repeating pattern. It is the opposite of crystalline. 2. Not fully developed or finalized: Describes ideas, plans, or thoughts that are vague, not fully formed, or not yet settled into a definite shape or conclusion.

Usage and Examples

• As an adjective describing physical state:
  • The volcanic glass was uncrystallised, giving it a smooth, non-granular texture.
  • The rapid cooling of the lava resulted in an uncrystallised mineral formation.
• As an adjective describing abstract concepts:
  • His proposal was interesting but still uncrystallised; it needed more detail.
  • She left the meeting with only an uncrystallised notion of what to do next.

Advanced Usage

• The term is often used in scientific contexts (e.g., geology, materials science) to describe glasses, gels, or amorphous solids.
• In figurative use, it describes the early, formative stages of creative or intellectual processes where concepts are still fluid and undefined.

Variants and Related Words

• Uncrystallized (adjective): The preferred spelling in American English. It has the same meanings as 'uncrystallised'.
• Amorphous (adjective): A direct synonym, especially for the first meaning (lacking crystalline form). It can also mean lacking a definite shape or character.
• Crystallised/Crystallized (adjective): The direct antonym. It means having a crystalline structure or, figuratively, having become definite and clear.

Synonyms

• Formless (especially for the first meaning)
• Unstructured
• Vague (especially for the second meaning)
• Indefinite
• Inchoate (formal, for the second meaning)

Antonyms

• Crystallised/Crystallized
• Crystalline
• Defined
• Definite
• Formed

Adjective

1. without real or apparent crystalline form
   • an amorphous mineral
   • amorphous structure
2. not finally or definitely formed
   • uncrystallized ideas