Along with the elements (fire, earth, air, and water) the qualities (cardinal, fixed, and mutable) are an important classification in astrology. The cardinal signs (Aries, Cancer, Libra, and Capricorn) are the initiators and pioneers with the drive to make something happen. The fixed signs (Taurus, Leo, Scorpio, and Aquarius) are the ones who concentrate and focus their energy to build on and sustain what is already there. The mutable signs (Gemini, Virgo, Sagittarius, and Pisces) are flexible, adaptable, and changeable, depending on the situation.
Signs of the same element are trine one another, and the trine is usually thought of as an easy, harmonious relationship that just flows. Whereas signs of the same quality are square or opposed one another. The square, for instance, is usually thought of as a more challenging, tense relationship that requires work. However in my experience, signs that are of the same quality, even though they are square or opposed one another, also have an affinity with one another, sharing a significant commonality in way of being and in values. Read more...
For instance, Leo (fire) and Scorpio (water) are both fixed and square one another. So they can both be stubborn, which can create problems, but they are also both known to be loyal, another fixed quality. That may actually create a deeper harmony than is typically attributed to signs that are square. In contrast, Leo and Aries (both fire) are trine and may be in the comfort zone together in their fiery, enthusiastic, and spirited temperaments. Yet, Leo is fixed and Aries is cardinal, so on the one hand the difference in qualities may compliment one another — for example, Aries will start something new and Leo with keep it going. But the difference in qualities may also be a point of contention — for example, Aries will be onto the next adventure while Leo is still attached to the old one.
Another example is Gemini (air) and Pisces (water). They are both mutable and square one another, so they might both be so changeable that there is no solid ground on which to stand. Yet on the other hand, they also both share an openness to all walks of life, adapting as necessary; Gemini is curious about all and Pisces naturally intuits the underlying oneness of all…
It is my practice to remember squares are not only negative, and trines are not only positive. All types of aspects, either within an individual birth chart, or when comparing two charts for compatibility, provide opportunities and gifts.