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The Arthur Ross Terrace will be closed this morning, Tuesday, October 21, for a private cultural observance. You many observe smoke and/or fire coming from the Terrace at that time. The FDNY has been notified in advance, and all safety precautions are in place. The Terrace will reopen at 1 pm.

B.3.2  The oldest rocks hero.jpg

The oldest rocks

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

      Audience: General

In This Section

B.3.2.1.1. Allende

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. 

B.3.2.2. Leoville. Variations of a theme B

Leoville

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

B.3.2.2. Clovis (No. 2)  Variations of a theme A

Clovis (No. 2)

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

B.3.2.3. Murchinson. Look closely

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.

B.3.2.4. Coolidge. Hidden CAis

Coolidge

The CAIs in Coolidge are no longer visible. 

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