The head line runs across the middle of the palm, starting at the thumb side and heading toward the outer edge. People assume it measures intelligence. It does not; plenty of brilliant people have short, plain head lines. What it measures is the style of a mind: how quickly it works, whether it prefers facts or ideas, whether it is cautious or bold, and how well it holds its focus. Those are more useful things to know about yourself than an IQ score.
Length
A long head line, reaching most of the way across the palm, belongs to someone who thinks things through and considers many angles before acting. It is the line of the planner, the researcher and the worrier. A short head line, stopping under the middle finger, belongs to someone who thinks quickly, decides and moves on, and who is impatient with long explanations. Short-lined people are often accused of not thinking; in fact they have finished thinking before the long-lined person has started.
Slope
A head line that runs straight across the palm is practical, logical and grounded. Its owner likes facts, plans and things that work, and is typical of Virgo, Capricorn and Taurus hands. A head line that slopes downward toward the wrist, toward the mount of the Moon, is imaginative. Its owner thinks in pictures and possibilities, and the steeper the slope the more the imagination dominates. A gentle slope makes a creative problem-solver; a very steep one makes a dreamer who may need help staying anchored, which is why palmists often see it in Pisces and Cancer.
Depth and clarity
A deep, clear head line is a mind that concentrates well. A faint line is a mind that scatters or tires. A line crossed by many small vertical lines shows worry or interruptions. An island in the head line marks a period of mental strain or confusion, and a break marks a change in the way the person thinks, often after a shock or a big decision.
Where it starts
The start of the head line is read together with the life line. Joined to the life line at the start, the person was cautious in youth and thinks with the family in mind. Separated from it by a small gap, the person is independent and confident. Separated by a wide gap, the person is impulsive and may act before thinking. Starting inside the life line, on the mount of Venus, the person is sensitive and easily hurt, and tends to take criticism of their ideas personally.
The writer's fork
A head line that splits into two branches at its end, one running straight and one sloping, is called the writer's fork. It shows a mind that can hold the practical and the imaginative at the same time, and is common in writers, teachers, lawyers and anyone who has to explain ideas to others. Gemini and Libra hands show it often. A three-way split at the end is rarer and belongs to people who can see almost any question from every side, a gift that makes them excellent advisers and slow deciders.
The simian line
In a small number of hands the head line and heart line merge into a single line running straight across the palm. This is the simian line. Its owner does not separate thinking from feeling: whatever they are interested in, they pursue with total intensity, and whatever they feel, they think about relentlessly. It is found in the hands of people who achieve a great deal in one field and in the hands of people who struggle to let anything go, and often in the same person.
The head line and the planets
In astrology the qualities of the head line belong to Mercury, the planet of thought, speech and calculation, and the mount at the base of the little finger is Mercury's place in the palm. A reader who finds a faint or broken head line will often look at that mount too, and at the person's sign. Emerald, Mercury's stone, and its gentler substitutes peridot and moss agate are the traditional supports for a mind that needs steadying.