Correlation between S&P 500 and gold

During the period 18-23 December both S&P 500 index and gold moved in relatively close harmony at average correlation of 0.72. Nevertheless, on weekly basis relationship was downward sloping and on Friday correlation coefficient reached 0.68. Possible explanation for downward trend could be fluctuations in S&P 500 index amid constantly decreasing price of gold until last workday. On Friday, both measures traded up, however gold advanced at higher pace than US benchmark index as metal traders took advantage of the unstable Greenback.