The aquamarine derives its name from aqua and mare meaning "sea water." It was poetically described by an ancient writer as "...a thousand leagues of sunlit sea imprisoned in a cup." Its color varies from deep blue to greenish-blue and is like the transparent sea itself. Aquamarine has long been considered the symbol of happiness and everlasting youth. The Egyptians, Greeks and Romans valued it highly, and many museums exhibit aquamarine specimens enhanced by old intaglio engraving and cameo carving. It was once the special talisman of ocean travelers, reputedly assuring them a successful voyage and safe return. The hopeful counted on it to renew married love, develop forbearance, cure laziness and further litigation.In the Middle Ages the aquamarine was said to bestow insight and foresight and, on the other hand, to have the power to induce sleep. The supposed power of the stone to fight evil was said to enable its wearer to conquer all wickedness. Water in which an aquamarine was soaked was believed to cure eye trouble, stoppage of breath and hiccups. Aquamarines were associated with the purity of the oceans and hence were credited with the power to keep its wearers clean in body and spirit. The ancients wore aquamarines engraved with the head of Neptune, the sea god, to protect them against the perils of the deep. In Egypt the stone is believed to have been used to invoke the aid of cunning water spirits and mighty heroes. In the ordering of the New Jerusalem, the gem was assigned to St. Thomas, the apostle, who made long journeys by sea to preach the faith.The lovely color in aquamarines is caused by a minute amount of iron compound. The aquamarine is the blue variety of beryl, the same mineral as emerald. The best aquamarines have great transparency and brilliance and often come in large crystals.In 1910 an aquamarine crystal was found in Brazil that weighed 243 pounds and was so transparent that objects could be seen through its long dimension of nineteen inches. The British Museum of Natural History has on display a flawless sea-green specimen that weighs 879.5 carats, and the American Museum of Natural History has several cut specimens, including a 271-carat Russian aquamarine, a 335-carat gem from Sri Lanka, an emerald-cut 144.5-carat Brazilian stone, and another one of top quality weighing 400 carats. Experts consider the most beautiful aquamarine ever discovered to be one that came from Brazil and was once owned by that country's emperor Dom Pedro. Aquamarines are mined principally in Brazil.In America the aquamarine was given an enormous boost in popularity in 1906 when President Theodore Roosevelt's daughter, Alice Roosevelt Longworth of "Alice Blue Gown" fame, was given a beautiful heart-shaped aquamarine by Vice President William Howard Taft as a wedding gift.