Journal of John S. Renfield, Esq.
Personal note: Add to 'Banks, Amelia' entry of index: Ungrateful harpy.
I woke up to a deluge of hysterical emails from the woman blaming me for the death of her cat and saying that she would tell all her friends how I was a terrible detective. I'm beginning to understand my namesake's scorn for the fairer sex.
I lost interest in Banks' hysterics when I went to take out the jewel -- the fading had picked up over the night, and by this morning it was losing color even as I watched. I lit one of my roommate's candles (cinnamon-scented; it was the only one I could find) and held the jewel over the flame with a pair of tongs. Had I not been watching closely I might not have even noticed, but the crack healed over minutely, and some color returned. The tongs quickly started to heat up, though, and I knew I couldn't hold it there for long. Instead I brought it to the communal kitchen and set it on a burner. Just before turning the dial I had a flash of insight and quickly raided the cupboards, finding boxes of sea salt and baking soda and mixing equal parts of each. Baking soda to bank the flames, sea salt because -- as I read somewhere once, though I'm not certain of it's validity -- it saps energy from magical items. I feel rather silly writing that now, but it seemed a good idea at the time.
When I turned back, the stone wasn't on the burner; I very nearly dropped the mixture, wondering how a thief could have slipped past me or if it had somehow gone off on its own. Fortunately I had enough presence of mind to pat my own pockets before panicking. I still don't quite remember putting it in my pocket, but there it was.
The stone healed even further with the heat of the burner. It stabilized with the crack halfways healed and the color returned to a healthy tone -- however 'healthy' a stone could be. I wonder whether it's the heat or the flame that helps it, but I don't have time to test it now.
I've googled a couple of jewelry stores and written down the nearest ones. Someone has to know something about this thing.
I'll report back tonight.