The "HGE" , "GE", or "HG" stands for hard gold electroplated, and the 18k refers to the type of plating (not that the piece of jewelry is actually 18k gold).
In other words, a piece of jewelry that is stamped 18k HGE is gold plated costume jewelry with little value.
Gold filled jewelry is made from joining or bonding a top layer of gold alloy to a base metal alloy and then rolled or drawn to the thickness required. Gold filled jewelry usually contains less than 5% gold alloy. Gold filled is sometimes stamped 1/20th 12k gold filled. Back in the 1970's, JCPenney took one of their rings that was stamped 14k and had it tested to determine exactly what its gold content was.
Gold eased on November 16th, 2012 and posted a sharp weekly loss as signs of global economic slowdown and fears of a U.S. recession dented bullion's inflation-hedge appeal. The metal posted a 1 percent drop this week and has fallen in five out of the past six weeks. News that the euro zone swung into a recession, disappointing U.S. economic data and Federal Reserve Chairman Ben Bernanke's negative outlook on the housing recovery all kept pressure on gold.