The Book of Wonder by Lord Dunsany

When Thangobrind the jeweller heard the ominous cough, he turned at once upon that narrow way. A thief was he, of very high repute, being patronized by the lofty and elect, for he stole nothing smaller than the Moomoo's egg, and in all his life stole only four kinds of stone -- the ruby, the diamond, the emerald, and the sapphire; and, as jewellers go, his honesty was great. Now there was a Merchant Prince who had come to Thangobrind and had offered his daughter's soul for the diamond that is larger than the human head and was to be found on the lap of the spider-idol, Hlo-hlo, in his temple of Moung-ga-ling; for he had heard that Thangobrind was a thief to be trusted.

Thangobrind oiled his body and slipped out of his shop, and went secretly through byways, and got as far as Snarp, before anybody knew that he was out on business again or missed his sword from its place under the counter. Thence he moved only by night, hiding by day and rubbing the edges of his sword, which he called Mouse because it was swift and nimble. The jeweller had subtle methods of travelling; nobody saw him cross the plains of Zid; nobody saw him come to Mursk or Tlun. O, but he loved shadows! Once the moon peeping out unexpectedly from a tempest had betrayed an ordinary jeweller; not so did it undo Thangobrind: the watchman only saw a crouching shape that snarled and laughed: " 'Tis but a hyena," they said. Once in the city of Ag one of the guardians seized him, but Thangobrind was oiled and slipped from his hand; you scarcely heard his bare feet patter away. He knew that the Merchant Prince awaited his return, his little eyes open all night and glittering with greed; he knew how his daughter lay chained up and screaming night and day. Ah, Thangobrind knew. And had he not been out on business he had almost allowed himself one or two little laughs. But business was business, and the diamond that he sought still lay on the lap of Hlo-hlo, where it had been for the last two million years since Hlo-hlo created the world and gave unto it all things except that precious stone called Dead Man's Diamond. The jewel was often stolen, but it had a knack of coming back again to the lap of Hlo-hlo. Thangobrind knew this, but he was no common jeweller and hoped to outwit Hlo-hlo, perceiving not the trend of ambition and lust and that they are vanity.