This document defines and provides examples of different types of pyroclasts: bombs (larger than 64 mm), cinders or lapilli (between 2-64 mm), and ash (less than 2 mm). Photos are included from Sunset Crater National Monument in Arizona, Snow Canyon State Park in Utah, and the Chalk Cliffs outside Bishop, California showing examples of bombs, cinders, and ash pyroclasts erupted from volcanoes.

1. Pyroclasts:
Rock fragments erupted from a
volcano

2. Bombs –
pyroclasts larger
than 64 mm in diameter

3. Bomb. DVNP. 3-10.

4. Visitors’ Center at Sunset Crater Nat’l Monument, AZ. 3-07.

5. Bombs and cinders. Sunset Crater Nat’l Monument, AZ. 3-09.

6. Bomb. Snow Canyon S.P., UT. 3-10.

7. With our favorite bombs. Snow Canyon S.P., UT. 3-10.

8. Cinders
(a.k.a. lapilli) –
pyroclasts between
2-64 mm in diameter

9. Bomb-to-cinder-sized pyroclasts.
Rock type? Snow Canyon S.P., UT. 3-10.

10. Climbing a pile of cinders and bombs. Snow Canyon S.P., UT. 3-10.

11. Inside a cinder cone at Snow Canyon S.P., UT.

12. Ash –
pyroclasts <2 mm
in diameter

13. “Chalk Cliffs” outside of Bishop, CA. 3-06.

14. Turning welded ash back into ash.
“Chalk Cliffs” outside of Bishop, CA. 3-06.

15. “Chalk Cliffs” outside of Bishop, CA. 3-06.

16. The End

17. Pyroclastically-named child with ash-sized particles.
Camp Verde, AZ. 3-07.