The sixth chakra is the mind and/or the third eye or mind's eye, associated with the intellect and situated (at its energetic activity point if you will) roughly between the eyebrows.
The seventh chakra is the crown, at the top of the head. It is the connection to what lies above, beyond the egoic mind, the higher or divine realm, where anything is possible.
Between those two points lies the 'unicorn point'. It is where a unicorn horn is located. Halfway between intellect and divine connection to the realm of infinite possibilities. The merging of those two forces can potentially make anything possible, depending on how well the 'software' is adapted to that mode of operation.
All of Equestria is filled with magic. Its nature is channeling, embodying it.
Pinkie Pie is utilizing magic, too, but because her governor facility - the intellect - is not optimized for control and focus, she practices what I (without claiming to understand it troroughly) tend to associate with "Miao Tong Dao", Lao Tzu's no-method path of enlightenment, where you simply wish things or states into existence. Since Pinkie Pie very much surrenders herself lovingly/passionately to happiness and thus an open and strongly radiating heart, that becomes the driving force for her magic. The governor that doesn't govern.
It might sound ironical, but as powerful as Twilight Sparkle's magic is, if there was a danger of Equestria's magic being weakened, hers would be more of a risk factor for that than Pinkie's. Twilight's magic is closest to our habits of generating electricity and other forces through machines, built by applying our intellect with very little use of divine connection. (We mostly work with what's already manifest in our realm and we build machines because we tend to externalize in the impatient pursuit of more power instead of focusing on personal growth by looking inwards.)
I embody various traits, but I definitely have a lot from a unicorn.
My Mayan birth horoscope is interesting in this regard. It describes me as a "flint", the divine spark of intelligence, mirror of reality, discriminating emotion from fact, cutting falsehoods away, tirelessly standing to protect, defend or cure others by personal sacrifice.
Flints can receive information on inter-personal troubles or the evil plots of others by reflecting in an obsidian mirror. (Socio-political research and personal life guidance in front of a computer monitor? ^^)
I'm kind of in a troubled relation with my galactic tone "10" though, the number of physical manifestation of intentions, ideas, hopes, fears, a powerful energy carrying great responsibility.