My tutor was surprised by my newfound interest in math, a subject that until then had not held my interest, and that he did not consider ladylike. To quell my relentless questions about the symbols and calculations I had seen in Papa’s notes, he grudgingly provided me with a hefty, dry tome by René Descartes and left me to try to decipher it while he turned his attention to teaching Georges his sums. My promise to Papa pushed me to glean what I could from the book. I had no clear plan or idea in mind, but I wanted to be ready to help when Papa returned from Venice with the skills to do the job. Meanwhile, André worked in the workshop, completing the settings on a few jewels the king would give as gifts. Papa considered him far enough advanced in his skills to be trusted alone on the king’s lesser projects, and André took these to heart, always happiest when he had free rein over a project and could add something of his own vision to it. He did not much miss Papa, at least not at first. I would work alongside him whenever I could, but I kept my study of mathematics to myself. If Papa had chosen not to share his secrets with his apprentice, it was not my place to reveal them.
Though we were insulated from the gem-cutters guild by our position among the king’s artisans, news had a way of getting quickly to the ears of the guild master. Papa had been gone from the city for scarcely more than a day before his wife, Madame Valin, came nosing around the workshop. Maman rolled her eyes at her arrival, but invited her to take tea in the parlor, knowing that any rudeness would only inspire more nosiness.
Madame Valin glanced covetously around the room before installing herself regally in Papa’s chair by the fireplace. She noticed me by the window, a heavy book before me, and wrinkled her nose.
“To what do I owe the honor of your visit, madame?” Maman asked, before she could offer her opinion of my studies.
Madame Valin squared her shoulders and spoke. “I heard a rumor that Master Pitau is away.”
Maman nodded.
Madame Valin waited with raised eyebrows.
Maman poured the tea.
“I understand he has gone looking for fine gold?”
“That’s right,” Maman replied, handing her a cup. I bit my lip to keep my expression from revealing anything. I was glad that Madame Valin’s sources had gotten it wrong. I was glad, too, that Maman did nothing to enlighten her.
“Then he will have gone to Spain, I suppose?”
“He will go wherever he needs to,” Maman said.
Madame Valin took a dainty sip from her cup before trying a different tack. “Of course. I am just surprised that he is working on the jewel’s setting, when he has not yet cut the stone. That seems an odd priority, don’t you think?”
She smiled as she waited for Maman’s reply, but her eyes had the sharp look of a vulture. Maman gave away nothing, only smiled blandly back.
“My husband is a master craftsman, and crown jeweler to the greatest court in Europe, madame. He knows well enough what he is doing.”
“But they say he has returned the Tavernier Violet to the king untouched. I hope he is not having any difficulty with the commission?”
“He would not leave the city without ensuring that the stone was in safe hands,” Maman said.
“But he hasn’t begun to cut it,” Madame Valin persisted.
“Do you think such a stone could be cut in a mere two months?” Maman said. “Surely your husband makes plans and models before he begins work on a treasure such as that.”
“Of course, of course,” she said, with a wave of the hand. “I only came to offer my assistance to you while your husband is away.”
“How very kind,” Maman said in a voice that carried no gratitude.
When our guest was finally gone, Maman gave a growl of disgust. “Insufferable woman!” she said.
“I’m glad you got rid of her,” I said.
“Oh, she’ll be back. But tell her nothing, Juliette.”
“Of course not!” I replied. I would never betray Papa’s secrets, but especially not to a nosey old cow like Madame Valin, and I said so.
Maman gave me an understanding smile, and a warning. “Don’t call her that, ma cherie. Always show her respect. She’s a dangerous person to offend.”
I wish now that I had heeded that warning, but even if I had, it might have done me no good.
* * *
Spring gave way to summer and Paris sank into swelter and fume. In the market stalls, the vegetables were limp, the cheeses sweated grease, and the meat and fish swarmed with flies. The reek of stagnant mud and sewage rose like a fog off the Seine.
Across the river on the Right Bank, the elegant homes of the nobility in the Marais district took on a still, cast-off air of abandonment. The Manufacture Royale saw no such quiet. Painters, sculptors, silversmiths, glassblowers, cabinetmakers, and weavers all worked on busily for the glory of the king, though our royal patron was at his leisure at Fontainebleau. The neighborhood sang from dawn until dusk with the pounding of hammers and chisels, the clatter of looms, and the creak and puff of bellows.
We kept working along with the rest. André had the projects Papa had left him, but had also begun a body of work of his own, to demonstrate the skills needed to advance out of his apprenticeship. The heat of summer was intensified by the forge in the workshop below our apartments. When it became unbearable, Maman would allow Georges and me to suspend our lessons. She and Georges would set out into the city on errands, but I seldom accompanied them. My promise to Papa bound me to the workshop. I wanted to keep an eye on André, who, when left to his own devices, was prone to overstep his bounds. I wanted to study Papa’s notes too. Whenever I was alone, I took the key from Papa’s hiding place and examined his papers. I copied calculations I didn’t understand, and at night, I sat on my bed, deciphering Papa’s greatest secret by the light of a single candle, and practicing equations until I understood them.
When I finally conquered the math, I began to read Papa’s notes on every stone he’d cut for the king. For each one, he had worked out the angles, but he had only been able to approximate those angles as he held the stone on the grinder by hand.
On every page he’d kept final notes that documented his disappointment and growing frustration at his inability to achieve accuracy. If he couldn’t cut precise angles on softer stones like topaz and amethyst, he would never succeed with a diamond.
That was why he had feared the Tavernier Violet, and why he’d flinched when the king forced it into his hands. I understood now, and I ached with worry. We had received word of Papa’s safe arrival in Venice, but no word that he had found any answers.
I was studying Papa’s notes about an especially complicated design one day in July when our maid rushed in from the street. She stood before me, wringing her hands and chewing her lip, until I looked up.