A perishable (and imported) store of value?
Perhaps the best idea of the crazy cost of spices can be formed by recalling that, in the eleventh century of our era, pepper, which today stands unguarded on every restaurant table and is scattered almost as freely as sand, was counted out corn by corn, and was certainly worth its weight in silver.
...Many states and towns kept their accounts in pepper as if it had been silver or gold. With pepper you could buy land, pay dowries, purchase the freedom of the city. Many princes assessed their taxes in weights of pepper. When, in the Middle Ages, you wished to describe a man as a bloated Croesus, you spoke of him as a ‘pepper sack’.
From Stefan Zweig’s book on Magellan.