Statistics on U.S. gold jewelry sales reinforce what high-end chain stores are saying: Demand for the yellow metal is on the rise.When John Green, president and CEO of Boston-based Lux Bond & Green, visited Highland Park, Texas, a wealthy community north of Dallas, in June 2014, he was struck by the number of women he saw wearing gold jewelry.  “They were moving away from white gold to yellow gold,” Green says.  Fourteen months later, the World Gold Council published a report, Gold Demand Trends Q2 2015, with data reinforcing Green’s conclusion: Gold jewelry sales in the United States are on the rise.  According to the report, the American market is “a slow and steady engine for jewellery demand.” The WGC says that the second quarter of 2015 marked the “sixth consecutive quarter U.S. gold jewelry demand has risen,” and that gold jewelry sales wer