The first step in choosing replacement crystals is to determine the grade of crystal you’d like to purchase. A crystal’s quality is graded by determining its’ lead oxide content. The lowest grade, crystalline, is glass with six to ten lead oxide content. The mid-grade glass, called half lead, must contain twenty-four to thirty percent lead oxide. Top grade glass, or full lead glass, constitutes a lead oxide content of over thirty percent. Higher amounts of lead oxide equate to more light refraction, making higher-grade crystals more adept at producing the telltale shimmer. Many different crystal types exist, with Strass, Turkish, and Egyptian being three of the leading varieties. Before purchasing, it is important to take note of your current crystal sizes, as some chandeliers may only fit up to a certain width.