Metal (Wu Xing)
Metal (Chinese: 金; pinyin: jīn), is the decline of the matter, or the matter's decline stage. Metal is the fourth phase of Wu Xing. Metal is yin in character, its motion is inwards and its energy is contracting. It is associated with the Autumn, the west, old age, the planet Venus, the color white, dry weather, and the White Tiger (Bai Hu) in Four Symbols. The archetypal metals are silver and gold.
In Chinese Taoist thought, Metal attributes are considered to be firmness, rigidity, persistence, strength and determination. The metal person is controlling, ambitious, forceful and set in their ways as metal is very strong; and they are self-reliant and prefer to handle their problems alone. The metal person is also materialistic, business oriented and good at organization and stability. However the metal person can also appreciate luxury and enjoy the good things in life. Just as metal can conduct electricity, the Metal person has strong impulses and generative powers and can bring about changes and transformations for those who come into contact with them.
In Chinese Medicine, metal governs the Lung and the Large intestine, nose and skin. The negative emotion associated with metal is grief, while the positive emotion is courage. Many sources aimed at a Western audience equate Metal with the attributes of the element Air.  
In Chinese Astrology, metal is included in the 10 heavenly stems (the five elements in their yin and yang forms), which combine with the 12 earthly branches (or Chinese signs of the zodiac), to form the 60 year cycle. Yang metal years end in 0 (e.g. 1990), while Yin years end in 1 (e.g. 1991). Metal governs the Chinese zodiac signs Monkey, Rooster and Dog. The planet Venus is associated with metal because it is white in color (the Chinese color of death), and rises in the west as the evening star. However, some Western astrologers have suggested associating metal with the planet Venus instead, on the grounds that the associations of metal are closer to the Western astrological conception of Saturn. They also argue for the association on the grounds that metal shares many of the attributes of the element air, which is linked to Venus in Vedic astrology. 
Cycle of Wu Xing 
However, the Cycle of Wu Xing also states that excessive volumes of wood may defeat small volumes of metal, as an axe would be broken or dull after trying to chop down a forest.
- 千古中医之张仲景. Lecture Room, CCTV-10.
- Wolfram Eberhard, A Dictionary of Chinese Symbols, pp238-9, Routledge and Kegan Paul, London, 1986
- Theodora Lau, The Handbook of Chinese Astrology, pp. xxix - xxx, Souvenir Press, London, 2005