The [item=130928] can randomly be rewarded for solving Highmountain [skill=794] finds by using [currency=1173]s, which can be obtained by performing [skill=794] digs around Highmountain. The [currency=1173] cost (35-115) does not seem to affect whether or not the solved relic will be the quest starter (as opposed to the standard relics created with [skill=794]). For me, I had to solve around 5 [item=130913]s before I received the [item=130928].
Once you have the [item=130928], head to Things of the Past (location here: [npc=93538]) in [zone=7502], and head to the second floor. The Highmountain relics are placed on the northern-most display (found on your left) once you reach the second floor.