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
Archibald Robertson (bishop) April) 1903, consecrated (ordained) as a bishop on 1 May (by Randall Davidson, Archbishop of Canterbury, at St Paul's Cathedral) and enthroned and installed at Exeter Cathedral on 5 May; he legally took up the See upon the confirmation of his election, which took place between his election and consecration (i.e. during April 1903). In 1912 Lollards Tower on the Exeter City Wall was rebuilt and several sculpted stone tablets displaying the arms of Bishop Robertson were set into the walls, including one over the arched entrance known as Bishop Carey's Postern. He served as diocesan bishop until 1916, when