Gold fill (also called gold overlay or gold-filled) is made by using heat and pressure to apply a layer of karat gold to a base of less costly metal. This produces a surface with karat gold. The minimum layer of karat gold must equal at least 1/20 of the total weight of the item. Gold fill is 50-100,000x thicker than normal gold plating, and far more durable.
Cubic Zirconia (CZ) stones are synthetic (manmade) gemstones. Like diamonds and natural zircons, cubic zirconias have a very high refractive index, for stellar sparkle!