Are there differences between friendships and spiritual friendships? If you ask a spiritualist, medium or a "clair" (clairvoyant, clairaudient, etc...), they will most likely say yes.
A friendship is based on many fundamental things. Trust, loyalty, support and companionship are among the basic requirements toward gaining the honor of being called "a friend". We laugh and cry with our friends, joke, entertain inside humor and so forth. We may have a best friend or two, people with whom we spend the majority of our free time, share our hopes and dreams and go through the trials and tribulations of jealousies, insecurities and resentments that often accompany friendship but are not strong enough to outweigh the benefits and blessings of those unions. These types of friendships help us grow, not only as human beings but as those of character and substance. They are truly a blessing.
Spiritual friendship exists between two souls whose paths cross not only for the spiritual growth of each, but for that of consciousness as a whole. You will find in these unions that many, if not most of your discussions incorporate enlightening spiritual epiphanies, realizations and vices by which to maintain a balance between spirit and human form. Spiritual friends have an earthly connection based on the common goal toward enlightenment. They too will share the aforementioned qualities, however they gather to "recharge" their spiritual batteries, to focus on the spirit rather than the consciousness of human existence and the trials of this life. They safeguard one another against the distraction of earthly problems and remind each other that this life is a small part of true existence and to maintain their composure and listen to their spirit for answers. These friendships can be between two beings in this life, or in the form of spirit guides and crossed loved ones. These friendships often have no "label". There will be an unmistakable spiritual purpose behind them that crosses the boundaries of labels or even sexual attraction, it transcends the body and mind.
As each of us progresses spiritually, we will find that more and more spiritual friendships will emerge, and many of those existing earthly friendships will begin to shift somewhat to present a balance between the two. These friendships have the benefit of a mutual growth experience and serve to guide as well, often in directions unforeseen and somewhat frightening.
As you can see, just as there is different kinds of love in this life, there are also different friendships, all serving toward the growth and bliss of each individual. Consider them blessings and do not be confused by their content. Our paths may be scattered, but ultimately, they lead to one place. Love.