Adrian Davies / Mother of Pearl, inside of Ormer shell (Haliotis)

Ingo Arndt / Green Abalone (Haliotis fulgens) shell interior from Baja California, Collection Meeresmuseum Ozeania, Riedenburg, Germany

Ingo Arndt / Blood-spotted Abalone (Haliotis spadicea) shell, Meeresmuseum Ozeania, Riedenburg, Germany

Jeff Rotman / Red Abalone (Haliotis rufescens) being held out of water. California, USA, Pacific Ocean. Model released.

LYNN M. STONE / Shell of Red abalone (Haliotis rufescens) in sand, Santa Barbara, California, USA

LYNN M. STONE / Close up view of Red abalone shell (Haliotis rufescens) photo shows three apertures / holes that living abalone had used for water exchange and the shell reveals the mother of pearl, or nacre, surface...

LYNN M. STONE / Red Abalone (Haliotis rufescens) shell interior showing nacreous mother of pearl. Santa Barbara, California, USA, February.

LYNN M. STONE / Red Abalone (Haliotis rufescens) shell interior showing nacreous mother of pearl. Santa Barbara, California, USA, February.

LYNN M. STONE / Red Abalone (Haliotis rufescens) shell interior showing nacreous mother of pearl. Santa Barbara, California, USA, February.

LYNN M. STONE / Close-up view of Red Abalone (Haliotis rufescens) shell. California, USA, February.

LYNN M. STONE / Close-up view of Red Abalone (Haliotis rufescens) shell. California, USA, February.

LYNN M. STONE / A Red Abalone (Haliotis rufescens) shell. California, USA, February.