Definition

Noun: A naturally occurring, amorphous (non-crystalline) solid formed when magma or other molten rock material cools too rapidly for crystals to form. It is a type of volcanic glass.

Usage

The term "natural glass" is used to describe a specific geological material. It is a mass noun, typically used without a plural form when referring to the substance in general. Specific types or pieces may be referred to in the plural (e.g., "obsidians are natural glasses").

Examples

• General Substance:
  • Obsidian is a common type of natural glass.
  • The rapid quenching of lava can result in the formation of natural glass.
• Specific Instances:
  • Archaeologists found tools made from natural glass at the site.
  • This specimen is a beautiful piece of natural glass.

Advanced Usage

• Scientific Context: In geology and material science, "natural glass" is studied for its properties and formation processes, contrasting it with synthetic or man-made glasses.
  • The study compared the fracture patterns in natural glass with those in industrial glass.

Variants and Related Words

• Obsidian: The most well-known type of natural glass, usually black.
• Tektite: A type of natural glass thought to be formed by meteorite impacts.
• Fulgurite: A type of natural glass formed when lightning strikes sand or rock.
• Pumice: A volcanic rock that can contain significant amounts of natural glass within its frothy structure.

Synonyms

• Volcanic glass (a direct synonym for the most common type).
• Mineraloid (a broader term for mineral-like substances that lack a crystalline structure, which includes natural glass).

Notes

"Natural glass" is a specific scientific term. In everyday language, people are more likely to refer to specific types like "obsidian." The term emphasizes the natural, non-man-made origin and the glassy, non-crystalline structure of the material.

Noun

1. magma of any composition that cooled very rapidly