Where can I get kyber crystals?

Could you please elaborate on where exactly one might acquire kyber crystals? Are they available in physical stores, or is it more of an online purchase? Are there specific websites or marketplaces dedicated to selling kyber crystals? Additionally, are there any safety precautions or regulations I should be aware of when purchasing or handling kyber crystals? I'm quite intrigued by their unique properties and would love to learn more about their acquisition process.