Chalk turquoise is a form of low quality natural turquoise that has the consistency of common writing chalk. Chalk turquoise is the most abundant type of turquoise found in the earth.
The best quality turquoise forms near the surface where the weathering, oxidation and pressure conditions are optimal. Chalk turquoise is usually found deeper in the earth, where it lacks the conditions to form the brilliant blue green colors and hardness we usually associate with turquoise. Chalk turquoise is usually a pale blue or green and often completely white. It is much softer compared to better quality turquoise.
To be usable in jewelry, chalk turquoise is crushed into a powder, infused with resins, glues and dyed making it harder and more vibrant in color.