"Snakes loomed large in Firdaus Begum's world-view and therefore in her family's too. "Snake wriggle, world jiggle," she liked to say, meaning that the great serpents burrowing away down by the roots of the mountains caused earth tremors when they moved. She knew many snake secrets. Under the shivering Himalayas, she said, there was a lost city where the snakes hoarded gold and precious stones. Malachite was a snake favorite and its possession bestowed good fortune on the possessor; but only if the stone had been found, not bought. "You can't buy snake luck," she warned. In general if a snake got in the house it was to be considered a blessing, something to be grateful for, and not only because it might gobble up the household mice... Snake protection was a thing all houses needed, and if you didn't have a snake to protect you then you'd better have some malachite stones instead." (From "Shalimar the Clown", by Salman Rushdie, page 56)

It's quite amusing to me, the malachite connection, for I've found this in my Egyptian snake studies. In the process whereby the newly 'transitioned' becomes every god prior to rebirth, the deceased declares as she becomes the snake goddess Wadjet, "Malachite glitters for me, I live according to my will, for I am Wadjet, Lady of the Devouring Flame, and few approach me,” (from "The Ancient Egyptian Book of the Dead", Carol Andrews, Raymond Faulkner, Page 49.)

I'm not sure entirely what the malachite connection is. I think the ancients used it as eye liner: