From The Voyages and Travels of Marco Polo
, as reprinted from John Pinkerton's edition by Cassell & Company in 1886:
After the province of Camul, a traveller entered the province of Chinchintalas... In this province there is a mountain, wherein are mines of steel, and andanicum, and also, as was reported, salamanders, of the wool of which cloth was made, which if cast into the fire cannot be burned; but that cloth is in reality made of stone in this manner, as one of my companions, a Turk, named Curifar, a man endued with singular industry, informed me, who had the charge of the minerals in that province. A certain mineral is found in that mountain which yields thread not unlike to wool; and these being dried in the sun, are bruised in a brazen mortar and afterwards washed, and whatsoever earthy substance sticks to them is taken away. Lastly, these threads so cleansed are spun like other wool, and woven into cloth; and when they would whiten those cloths, they cast them into the fire for an hour, and then take them out unhurt whiter than snow; after the same manner they cleanse them when they have taken any spots; for no other washing is used to them, besides the fire. But with regard to the salamander, or the serpent, which is reported to live in the fire, I could find nothing of such a creature in the east countries. They say there is a certain napkin at Rome woven in Salamander wool, wherein the handkerchief of the Lord is kept wrapped up, which a certain King of the Tartars sent to the Bishop of Rome.