堆積岩

1. Origins, structure, and basic meaning

• Structure: 堆積岩, read たいせきがん, combines 堆積, accumulation or deposition, with 岩, rock.
• Basic usage: It names a rock type, whether discussing a specimen from a layer or the process by which sand and mud harden into rock.

2. Common pitfalls and similar expressions

• Specimen versus formation
  • 堆積岩を観察する treats it as a specimen, whereas 堆積岩になる describes material becoming that type of rock.
• Do not drop 岩
  • 堆積 names accumulation or deposition; 堆積岩 names the resulting category of rock.