Selenite's spiritual meaning centers on its use for spiritual cleansing, mental clarity, and connecting with higher consciousness. It is associated with the moon goddess Selene, representing purity, divine light, and the ability to clear negative energy from other crystals, spaces, or a person's aura. Its use is believed to activate the crown and third eye chakras, promote peace, and enhance intuition and spiritual guidance. 
Key spiritual properties and uses
Cleansing and purification: Selenite is known for its ability to cleanse and purify energy. It is used to clear stagnant energy from other crystals, homes, and oneself.
Mental clarity and focus: It is used to clear mental fog, enhance focus, and improve decision-making. Placing it on the head is believed to clear mental confusion.
Spiritual connection: It is seen as a bridge between the physical and spiritual worlds, helping to connect with higher guidance and the angelic realms.
Chakra activation: Selenite is strongly associated with the crown and third eye chakras, which are linked to spiritual awareness, intuition, and higher consciousness.
Protection: Many believe it creates a protective shield against negative influences. It has been traditionally placed at doorways to ward off bad spirits.
Meditation and peace: It is a popular crystal for meditation, helping to bring a sense of peace and calm and making it easier to receive spiritual insights. 
How it's used
Energy cleansing: Place other crystals on a selenite charging plate to cleanse them.
Space clearing: Place selenite towers or wands in the corners of a room to create a serene and protected environment.
Meditation: Hold it during meditation or place it on your forehead to connect with higher consciousness.
Aura cleansing: Some healers use selenite wands to cleanse and balance the aura.