Crystals are very popular, but quality and price are varied. Also, some can be contained malicious, so you should be a connoisseur of them.
Shu-san recommended Celestites in the other video last time and he has highly recommended, especially, Azurites today.
Azurites are Edgar Cayce’s recommendation, either.

They are reasonable, produced in many countries. They affect the crown chakra. You can feel it even watching this video.
Azurites make the crown chakra awaken.

The big one is good, but also the small one has the similar power (the high quality of energy). Especially, shiny crystallized ones are better.

It doesn’t matter any sizes and any producing countries. Any Azurites are great energy.

Azurites are the one only that anyone can get the same quality of energy, although Crystals are not.
The gemstones are the really good way to feel cakras, qi-energy and spiritualities. Shu-san believes Azurites are the one of the best of them.