Cracked CZ is a form of cubic zirconia, its appearance modified to look as if it is cracked on the inside, and therefore giving it the name cracked CZ.
Smoky Quartz is a grey and translucent variety of quartz. It ranges in clarity from almost complete transparency to a brownish-gray crystal that is almost opaque. Like other quartz gems, it is a silicon dioxide crystal. It was not commonly used in the ancient times, but it has recently become a popular gemstone used for jewelry.