Pearl
A gem that turns up in wildly separate traditions.
Greek margarī́tēs, pearl, gave the name Margaret — and Margaret went on to become one of the most widely borne girls' names in European history, producing Margarethe, Marguerite, Margarita, Margit, Margrét, Rita, Greta, Meg, Peggy and dozens more. Few name elements have branched further.
The Greek word itself was borrowed from further east, and the ultimate source is debated; a Sanskrit origin has been proposed and is neither settled nor dismissed. What is clear is that the word travelled the same routes the pearls did, from the Gulf and the Indian Ocean into the Mediterranean.
Arabic lu'lu' and durr both name pearls, and the pearl-diving economies of the Gulf gave the vocabulary a prominence in that region's naming that it does not have elsewhere. Sanskrit muktā means both pearl and released or liberated — the same word, from the sense of the pearl being freed from the shell — which gives names on this page a double reading in Indian usage.
The pearl is unusual among gemstones in that it is organic, requires no cutting, and comes out of the water finished. A good deal of the symbolism attached to it in every one of these traditions follows from those three facts.