Definition: A shelly concretion, usually rounded, and having a brilliant luster, with varying tints, found in the mantle, or between the mantle and shell, of certain bivalve mollusks, especially in the pearl oysters and river mussels, and sometimes in certain univalves. It is usually due to a secretion of shelly substance around some irritating foreign particle. Its substance is the same as nacre, or mother-of-pearl. Round lustrous pearls are used in jewellery.
Alright class, settle down, let’s take a look today, At something beautiful and lovely, come what may! We've got our dictionary open, bright and clear, Let's break down the meaning of "pearl," it’s perfectly near. (Pause for emphasis) "A shelly concretion," that’s where we start, Not a stone from the mountains, playing a part! It grows inside creatures, quite small you see, Like oysters and mussels, happy and free. (Tap rhythmically on desk) “Rounded” it is, with a shimmer so grand, A “brilliant luster,” throughout the land! – Or ocean, that’s where they expand. With tints of pink, or white, or even blue, A lovely spectrum, for me and for you! It forms when something bothersome does stray, An irritating particle, come what may! The mollusk secrets a substance so neat, "Nacre," called mother-of-pearl, oh so sweet. (Smile warmly) And finally, class, it’s worth noting with glee, “Round lustrous pearls” are prized for jewelry! So there you have it – a pearl's lovely guise, A natural wonder, before your eyes! Any questions? Don't be shy, let’s discuss, Understanding the science is truly thus!