Below is an article on market correlations.
Market Correlations – Statements and Assumptions | 20th June, 2017

http://elliottwavegold.com/2017/06/market-correlations-statements-and-assumptions-20th-june-2017/

Using the same chart settings it appears TLT-GLD hardly correlates with nominal price of gold.

But US bond to USD ratio well correlates with the nominal price of gold.

TSI Blog states:”There are fundamental reasons for the existence of a positive correlation between the bond/dollar ratio (the T-Bond price divided by the Dollar Index) and the US$ gold price, but I currently don’t have the time or the inclination to go into these reasons. Instead, for the sake of brevity I present the following chart-based comparison of the gold price and the bond-dollar ratio. The positive correlation is obvious and is evident over much longer periods than the 3-year period covered by this chart.
Compare both the chart and determine which correlates better with price of gold????

The coefficient is -ve in case of TLT/GLD while the USB/USD coefficient is mostly above the +0.75. Lately it is not correlating while the coefficient is going down.