The earliest example of ceremonial gold is the burials at Nahal Kana in modern day Israel, which was about 4000 BCE. Graves were uncovered containing about 8 gold rings.Grave goods are usually the best source for understand any prehistoric civilizations and writings. Ceremonial burials have been recognized as early as 100,000 BCE. By purposely burying a body with an object you infer the object has meaning to that person or to that culture. So gold probably had at least some value before this time, but this is the earliest example of it having serious significance.

Sources- הזהב העתיק ביותר בעולם/ The Oldest Gold in the World (on the occasion of the exhibition in the Israel Museum) VLADIMIR G. ZBENOVICH and ולדימיר זבנוביץ Mitekufat Haeven: Journal of the Israel Prehistoric Society /מתקופת האבן כרך כ"ו‎ (תשנ"ה/ 1994-5), pp. 159-173

Earliest Gold Artifacts in the Levant A. Gopher, T. Tsuk, S. Shalev and R. Gophna Current Anthropology Vol. 31, No. 4 (Aug. - Oct., 1990), pp. 436-443

I may be wrong, however I believe this is more of an anthropology or archaeology question than a historical one. The first use of gold as a trinket or currency is certainly very prehistorical.