One of the key characteristics of a polki's clarity is it's inclusions. Inclusions are small imperfections within a polki that are created due to the extreme pressure and heat that polkies experience when they form.
Sometimes, these inclusions may lead you to believe that the polki is cracked. A very simple and DIY test to clarify your doubt, is nail test: try running your nail lightly on the polki - if it stops, it's a crack.. else not.
We hope that you found this information useful!
In case of any questions, please reach out to us - happy to help!