Europeans used to call Long Xianxiang "amber fragrance". In the Middle Ages, it may be that Arabs began to use amber to refer to a kind of Gu Song juice condensate produced along the Baltic Sea. This kind of thing is called "sack" by the Romans, "yellow spice" by the French and "amber" by the British. This is why the British borrowed the French word "grey amber" to refer to the "Long Xianxiang" produced by whales.