Gemstone the stone such as color zoning (the uneven distribution of coloring within a gem) and asteria (star effects). The Greeks, for example, greatly valued asteria gemstones, which were regarded as powerful love charms, and Helen of Troy was known to have worn star-corundum. Aside from the diamond, the ruby, sapphire, emerald, pearl (not, strictly speaking, a gemstone), and opal have also been considered to be precious. Up to the discoveries of bulk amethyst in Brazil in the 19th century, amethyst was considered a "precious stone" as well, going back to ancient Greece. Even in the last century certain stones such
Gregory S. Stone the Pew Fellowship in Marine Conservation in 1997 and in 1990 won a postdoctoral award from the National Science Foundation for his work on marine science in Japan. In 1989, Stone received the John A. Knauss Marine Policy Fellowship and in 1986 the National Science Foundation and U.S. Navy Antarctic Service Medal. In 2013, Stone received the Wyland Foundation ICON Award, the NOGI from the National Academy of Underwater Arts and Sciences in 2015, and in 2014 was named the Boston Sea Rovers Diver of the year. Gregory S. Stone Gregory Schofield Stone (born 1957 in Boston, Massachusetts) is an