It can be white or blue or black, Humped or have a horn. And when it talks it sings its menuets, as it's travelling the depths.
With four oars it swims but it is always at home.
Its back is like armor, tougher than chrome.
What is it?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.See answer
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