PRECIOUS-Gold near six-week low as dollar firms, Korea tensions ease

* Dollar index rises back towards Friday's three-month high * GRAPHIC-2018 asset returns: http://tmsnrt.rs/2jvdmXl (Updates prices, headline; adds comment, second byline, NEW YORK to dateline) By Renita D. Young and Jan Harvey NEW YORK/LONDON, April 30 (Reuters) - Gold prices fell to the lowest in nearly six weeks on Monday as the dollar strengthened and easing tensions on the Korean peninsula helped boost appetite for higher risk assets such as stocks. Spot gold los