Crystals can be brought In all shapes and sizes and whilst we may just buy them for the way they look or purely for the intention of that crystals and I personally never used to realize that the shape of a crystal did actually influence the way it worked.so i decided to quickly put something together to show the influence of the shapes.
Single point crystals: these focus energy In one direction and can only either transmit or Draw energy one at a time. You can only transmit energy or draw once at a time.
Double pointed crystals: These crystals can Both draw and transmit energy at the same time and so are useful for balancing opposing forces.
Crystal clusters: radiate energy of the crystal to the surrounding area.
Geodes: amplifies energy and slowly releases it into their surroundings.
So these are some of the shapes and how they influence the way the crystals work. These are from some books I have and my grimoire.