The oldest rocks

  • Exhibition Text

    • Crystals containing calcium and aluminum date to the beginning of the solar system.

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  • For Educators

    • Topic: Astronomy

      Subtopic: Planets

      Keywords: Astrophysics, Aluminum, Chondrites (Meteorites), Calcium, Solar System--Origin, Astrogeology

      Audience: General

In This Section

Allende (AMNH 4880)

Allende (AMNH 4880)

This fragment of Allende contains two kinds of calcium-aluminum inclusions (CAIs): round and irregularly shaped. Round CAIs melted and resolidified at some point in their history. 

Leoville

Leoville

Not every primitive meteorite contains calcium-aluminum inclusions; some meteorites, like Leoville, have abundant CAIs, whereas others, like Clovis have none.

Clovis (No. 2)

Clovis (No. 2)

Not every primitive meteorite contains calcium-aluminum inclusions; some meteorites, like Leoville, have abundant CAIs, whereas others, like Clovis have none.

Murchison (AMNH 4378)

Murchison (AMNH 4378)

The tiny white calcium-aluminum inclusions, or CAIs, in Murchison are exceptionally small—much smaller than the CAIs found in meteorites like Allende.

Coolidge

Coolidge

The CAIs in Coolidge are no longer visible.