The term 'emerald, for one' is a reference to a type of gemstone. The crossword solutions for this term are GEM (3 letters), ISLE (4 letters), CITY (4 letters), and BERYL (5 letters). GEM is an abbreviation for gemstone, which is a type of mineral that is cut and polished to be used as jewelry or other decorative items. ISLE is an abbreviation for island, which is a landmass surrounded by water. CITY is an abbreviation for CITY, which is a large and densely populated urban area. BERYL is an abbreviation for BERYL, which is a mineral composed of beryllium, aluminum, and silicate. Emeralds are a type of BERYL, and are known for their deep green color.