He would take time to really think about what she asked and consider the material when she spoke, especially with the frown she gave. As far as he knew, and from what he read, the pliability of the circle was essential in casting; more rigid materials and circles were preferred over softer ones due to the risk of the circle breaking. But, after enchantment, the circle was finished, and it relied on the item to hold the magic and what it was made of. He knew that the natural makeup of the material was critical; if he were trying to enchant plastic, he would be lucky if the enchantment worked even once due to magic's reaction to unnatural materials.
“No, not with my life, but that isn't because of the material. I do trust it, however, to hold the enchantment,” Markus answered. He wouldn't ever be willing to risk his life on a single thing going well; he was one to believe in redundancy. “I don't need the magic to last too long when activated; besides, if it did, then the lasting shield might harm me more than the attack itself. I need a quick effect that allows me to act, which this is sufficient for.” He knew that if the pendant were damaged, it would require repair and perhaps even re-enchantment, but that was acceptable and maybe even preferable if he continued to refine this enchantment.
“Pewter is subpar regarding manufacturing materials, but it should be fine for enchantment unless you can tell me otherwise. Its quality is arbitrary based on its value and manufacturing time, neither of which magic cares about. It is a pliable alloy of all-natural metals, meaning it can hold intricate details better than harder metals. The risk then comes with its ability to take a hit, meaning I must be careful. But that is true of any soft metal. Not because of the magic but because of physics and the risk of damage from scratching it against a wall, for instance.” Markus finished explaining his thought process; however, he was very open to correction. If the enchantment worked as intended, he didn't have to worry about magic damaging the item, not with its nullification effects; in this case he thought, it was the mundane he needed to worry about.