For most of its recorded history tourmaline was sold as ruby, as emerald, as sapphire — not out of dishonesty but because nobody could tell. Its story is the story of a mineral slowly getting its own name.
Dutch traders bring parcels of coloured stones from Ceylon. The Sinhalese word attached to them, turmali, means roughly mixed gems — the local name for material that came in too many colours to sort. The word becomes tourmaline, and the mineral is, from the beginning, defined by the fact that it refuses a single colour.
Warmed near a fire, the stones are found to attract ash and small particles, then repel them. The Dutch call the mineral aschentrekker. What they had found, without a word for it, was pyroelectricity: tourmaline develops an electrical charge when its temperature changes. No other common gem does this, and it remains the mineral's strangest property.
King Gustav III of Sweden presents Catherine the Great with a large red gem carved as a bunch of grapes, long held as a ruby of extraordinary size. It is a rubellite tourmaline of roughly 255 carats. It sits in the Russian Diamond Fund still — the most famous example of the confusion that follows this stone through its history.
Two students find green tourmaline crystals in the roots of a fallen tree at Paris, Maine. Mount Mica becomes the first commercial gem mine in the United States, and American tourmaline enters the trade.
The pegmatites of San Diego County — the Himalaya mine above all — produce pink tourmaline in quantity. The largest buyer is the Chinese imperial court: the Empress Dowager Cixi has the material carved and set. Her death in 1908 and the fall of the dynasty remove the market almost overnight, and the Californian mines close.
The lithium-rich species that accounts for nearly every gem tourmaline is named after the island of Elba, off the Tuscan coast, where it was described. Rubellite, indicolite, verdelite and Paraíba are all elbaite; they differ only in which elements the crystal happened to take up.
After years of digging into a hill at São José da Batalha in the state of Paraíba, Brazil, Heitor Dimas Barbosa reaches material of a blue-green nobody in the trade has seen. It reaches Tucson in 1990 and prices move within a season. Analysis later shows the cause: copper, an element never before found colouring gem tourmaline.
Copper-bearing tourmaline appears in Nigeria, in the Oyo State pegmatites, and from about 2005 in far greater quantity at Mavuco in the Alto Ligonha district of Mozambique. Both are accepted under the Paraíba name, which is defined by chemistry rather than by geography. Laboratories separate the three sources by trace elements — gallium, germanium and lead run higher in Nigerian material, magnesium and zinc in Brazilian.
Three centuries of a stone being called something it was not is not a charming anecdote — it is the reason this trade still needs a laboratory report and a plain description.
The colour guide