Crackle Quartz

Crackle quartz is a crystalline quartz that has been intentionally fractured by people. They usually heat rock crystal or slightly translucent quartz to a high temperature, then suddenly quench it in cold water. The shock of sudden cooling causes a network of tiny fractures to propagate through the quartz. The result is a transparent colored stone that sparkles when it is moved under bright light. The sparkles are produced as light enters the stone, strikes an internal fracture surface, and reflects back to the eye of the observer. 

This Quartz is known as Fire and Ice Quartz it contains multiple rainbows within. Quartz is the master healer of the crystal world and counteracts negative energy.  It contains two elements light/dark with Yin/Yang energies to bring harmony.  Perfect for the Chakras as it contains pure life force energies that empower us and brings all-over physical and auric cleansing and healing.  Crackle Quartz is quartz that has been superheated and may have color-infusions.

Source 

https://rocktumbler.com/blog/crackle-quartz/

Image Source:

Chy Jewels