Turquoise Chalk or Chalk Turquoise is not actually chalk; it 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. On the turquoise hardness on the Moh’s scale, chalk turquoise can range from a 2-3. Really good quality turquoise usually scores above 5.
Chalk turquoise is so soft that it is not ideal for making jewelry. However, because this low grade is so accessible and people love turquoise, it is also the most common type of turquoise used in jewelry. 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. This is called reconstituted turquoise. The slabs of reconstituted turquoise are cut into cubic blocks and sold to jewelers on the market. Jewelers can then shape this plastic-like turquoise chalk block material into a desired shape, such as a jewelry cabochon. These cheap cabochons are used to make cheap jewelry.
So the next time you are shopping for turquoise jewelry, keep this in mind. If a piece seems cheap, it probably is cheap because it’s made with cheap materials. If you don’t care and like how the piece looks, then you can find some great deals. If you want of find a piece with good quality turquoise, then you need purchase from a reputable dealer and don’t be afraid to ask questions about the stones. Don’t ask if the turquoise is real! Ask where the stones came from, if the stones are natural, if the stones are enhanced, if the stones are stabilized or if the stones are reconstituted.