A story from The Autobiography of Cellini. The picture is one of his sculptures.
Messer Durante of Brescia hired a soldier to administer a deadly liquor in my food. The poison was to work slowly, killing me at the end of four or five months. They resolved on mixing pounded diamond with my food. Now diamond is not a poison in the true sense of the word, but it retains its edges and does not act like other stones because of its incredible hardness. When every other stone is pounded, the edge is lost; the fragments become blunt and rounded. Diamond alone preserves its qualities; if it enters the stomach together with food, the peristaltic motion of digestion brings it into contact with the lining of the stomach and the bowels. The action of fresh food forces it farther inwards; eventually it perforates the organs and causes death. Any other sort of stone or glass mingled with food does not stick but passes through with the food.
Now Messer Durante entrusted a diamond of trifling value to one of the guards. It is said that a certain Lione, a great enemy of mine, was commissioned to pound it. The man happened to be very poor, and the diamond was worth many crowns. He told the guard that the dust he gave him was the diamond properly ground down. The morning when I took it, they mixed it with all I had to eat; it was a Friday, and I had it in salad, sauce, and stew. That morning I ate heartily, for I had fasted on the evening before and that day was a festival. It is true that I felt the food scrunch beneath my teeth, but I expected nothing out of the ordinary.
When I finished, some scraps of salad remained upon my plate; a few glittering splinters caught my eye. I collected them and took them to the window, which let a flood of light into the room; while I was examining them, I remembered that the food I ate that morning had scrunched more than usual. After applying my senses strictly to the matter, the verdict of my eyes was that they were fragments of pounded diamond. When I saw this I gave myself up for dead, and in my sadness began speaking holy prayers. I was sure that I had been sold out and murdered. For a whole hour I prayed fervently to God, giving thanks to Him for such a merciful death. Since my stars had sentenced me to die, I thought it a good bargain to escape life so easily. I was resigned, and I blessed the world and all the years which I had passed in it. Now I was returning to a better kingdom with the grace of God, which I thought I had certainly earned.
While I stood turning these thoughts over in my head, I held in my hand some particles which I firmly believed to be real. Since hope never dies, I felt myself lured on by a vain thought. I took up a little knife and a few of those specks, and placed them on an iron bar of my prison. Then I gently brought the knife’s point down upon the pieces and felt them crumble. When I examined the particles with my eyes, I saw the truth. Suddenly I was clothed again with hope, and said: “This isn’t a diamond from my enemy but poor soft stone, which can’t harm me at all.”
I had been resolved to remain quiet and die peacefully; now I made other plans, but first I thanked God for poverty; for though poverty often brings men to death, on this occasion it had been my salvation. Messer Durante, my enemy, or whoever it was, gave a diamond worth over a hundred crowns to Lione; poverty made him keep this for himself and pound a soft greenish beryl instead, thinking wrongly that because it also a stone, it would have the same effect.