Forming a Grid

Crystal Grids
can be used
to protect a room  place single terminated quartz crystals with black tourmaline in each corner of the room pointing outwards 

to energise a room  place clear quartz points in the four corners pointing inwards and hang one crystal from the ceiling at the centre of the room, forming a pyramid grid
 
to charge an object  place 4 or 8 crystals around it, aligned to the directions of the compass
to send energy to someone place crystals around a picture of the person and hold them in your heart in white light with the energy you want to send them ( for ethical reasons I suggest you asked their permission to do so )

Crystal grids can be formed with any type of crystal - however, clear quartz single or double terminated points are preferred to direct the flow of energy.

Clusters or tumbled / polished stones can introduce a specific quality to the grid.

Choose stones that correspond to your intention for the grid. You could place a grid around a room to create a favourable energy for the function of the room. For example Rose Quartz to bring a loving energy to the bedroom, Amethyst for meditation, Citrine for studies, Hematite for grounding and protection.

See also Gemstones A-Z for some spiritual properties of crystals and gemstones