Sentence:  "This happens to be my last voyage. But even so, I intend no coercion. If he does not value the <WSD>alicorn</WSD> to the extent of ten thousand Spanish dollars, I'll keep it myself. I'm rather fond of the thing. You see, it's a genuine unicorn's horn, and they're exceedingly few." 
Meaning of the word marked with <WSD> tags:  The horn of a unicorn considered as a medical or pharmacological ingredient.