Selenite coaster/power plate
Purification, Tranquility, Positivity, Clarity, Activation, Protection
It can help cleansing congested energy from the physical, mental, etheric, and auric bodies and since It is a great stimulator for the higher chakras, it can also be very useful on enhancing communication with the Higher Self, Guides, and Angels.
Selenite carries very angelical energies and is related to the the white rays of light.
It is known for being a great cleansing crystal, helping other crystal cleans themselves. This could be the main purpose of the plates, on which crystals can be placed and enjoy a peaceful angelical cleansing session!
Chakras: 3rd Eye, Crown
This information is purely metaphysical in nature and is by no means medical.
The shape, size and color of the crystals may varieties from the pictures even dough will have the same uses :)