was first drawn to the magic of silver's luster while standing as a child in the British Museum, gazing at a finely polished metallic silver mirror and asking, "Why?" Not having the benefit, at the time, of a college education and a second degree majoring in transition-metal chemistry, the question went unanswered.

Today, however, silver's time-honored and unique ability to reflect almost 100% of the light that falls on it is, for me, more easily explained. It's a result of teamwork between light and the outermost single electron. This electron, when activated by light, absorbs energy that enables it to jump into a higher, faster orbit around the atomic nucleus. This new orbit cannot, however, be permanently sustained--the attraction of the nucleus is too great. As the electron falls back to its original orbit, its absorbed energy is radiated outward in the form of light, resulting in the eye-pleasing radiance known as luster.

To the ancients, however, silver was an object of wondrous beauty, imbued with the mystic qualities of the moon, whose dark and mysterious nature it seemed to mirror. My personal fascination with silver began through admiration of Greek and Roman artifacts, but it certainly did not end there. My love of all things ancient revealed, after years of study, a fundamental, almost deific, relationship between man and this indispensable metal that has perpetuated into modern times, albeit in a more subtle form.

Name: From the Anglo-Saxon seolfor, silver. The symbol is from the Latin word for silver, argentum.
Atomic mass: 107.87.
History: Known since ancient times. Ancient slag dumps indicate that silver was separated from lead as early as 3000 B.C.
Occurrence: Silver occurs in ores including argentite and horn silver and in conjunction with deposits of ores containing lead, copper, and gold.
Appearance: White metallic solid.
Behavior: Silver has the highest electrical and thermal conductivity of all metals and possesses the lowest contact resistance. It is very ductile and malleable.
Uses: Used to make photographic film, tooth filings, silverware, mirrors, batteries, photosensitive glass, and as an electrical conductor. Silver iodide is used for seeding clouds to produce rain.

IN HIS IMAGE Alexander the Great minted silver coins emblazoned with his image. © THE BRITISH MUSEUM

The Druids of the ancient British Isles harvested holy mistletoe and oak leaves with finely engraved and enchanted silver sickles. The very shape of these swords is reflective of the image of the crescent moon, the heavenly body silver was believed to represent on Earth. Alexander the Great, a devotee of the Olympian Pantheon, believing himself to be a god in life, was after death worshiped in association with the sun god Helios. Was there a connection between this cult and the gifting of highly polished and quite valuable silver shields to Alexander's most seasoned veterans, the Hypaspists, an elite group within the Agema (royal guards)? This group came to be known as the Agryaspids, or Silver Shields, and became as famous as Caesar's 10th Legion or Napoleon's Old Guard are to us now.

One can visualize the scene as an enemy column advanced toward the Macedonian line, when, on Alexander's command, the shields and the full power of the sun's rays were brought to bear. It is not hard for me to imagine Alexander claiming the authority and divinity of the sun at such a time--hence, perhaps, his association with it after life.

The relationship between silver and the history of humankind has endured. Silver has a number of unique properties that set it apart from other metals. These include strength, malleability, and ductility; electrical and thermal conductivity; and, as already referenced, high reflectance of light and a lesser known but increasingly important medical application as a bactericide.

History reflects man's almost lustful quest to acquire silver, and our modern vocabulary is replete with references to it. Indeed, over the years, silver, like no other metal, has become synonymous with beauty, wealth, style, health, and mystique. For example, the phrase "born with a silver spoon in your mouth" is a reference to wealth and health. In the 18th century, babies who were fed with silver spoons were found to be healthier than those fed with spoons made from other metals, and silver pacifiers have subsequently found wide use in the U.S. because of their beneficial health effects.

To ask for silver service would be to expect the very best. To find oneself looking for a silver lining is to hope for a benevolent outcome to an otherwise uncomfortable and adverse situation. A star of the silver screen is in part a reference to the use of silver in the film industry but also, again, a reflection of its association with beauty and style. Even in nature, the silver birch is regarded as a tree of elegance, commonly referred to in northern Europe as the "Queen of the Forest."

Finally, if you were a lycanthrope or indeed a vampire, according to myth, to be struck by a silver-tipped arrow or bullet would result in instant and irrevocable death. For me, the great author J. R. R. Tolkien so eloquently captured all of the aforementioned characteristics when describing the Mirror of Galadriel in the epic trilogy "Lord of the Rings."

We end as we began, with a reflection of man and his endless interaction with this most noble of metals. For me, silver represents true majesty among the elements. If gold claims to be its king, silver must surely be its queen.

Alan Shaw is president and chief executive officer of Codexis. He has had a long career in the fine chemicals industry, including with Clariant, Archimica (BTP plc), Chirotech Technology Ltd., and ICI.


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