Here are some different takes on the geometry of the chakra system.
Symbols of the chakras
Law of One
The law of one is channeled material by a being identified as “Ra”. Learn more about the law of one material here.
Here is what the Law of One material has to say about the geometries of the chakras.
Questioner: What do you mean by crystal structures?
Ra: I am Ra. Each of the energy centers of the physical complex may be seen to have a distinctive crystalline structure in the more developed entity. Each will be somewhat different just as in your world no two snowflakes are alike. However, each is regular. The red energy center often is in the shape of the spoked wheel. The orange energy center in the flower shape containing three petals.
The yellow center again in a rounded shape, many faceted, as a star.
The green energy center sometimes called the lotus-shape, the number of points of crystalline structure dependent upon the strength of this center.
The blue energy center capable of having perhaps one hundred facets and capable of great flashing brilliance.
The indigo center a more quiet center which has the basic triangular or three-petaled shape in many, although some adepts who have balanced the lower energies may create more faceted forms.
The violet energy center is the least variable and is sometimes described in your philosophy as thousand-petaled as it is the sum of the mind/body/spirit complex distortion totality
Traditional Chakra Image from: http://www.awaken.com/2015/06/chakras-in-a-nut-shell/