Godstones (2010)

From publisher blurb:

Of all the enigmas in the Kethrian family of worlds, none is more puzzling than that of the Earthmasters. Their power was godlike and their nature unknown. All that remains of them are their deserted sites and a precious few of their amazing artifacts, the greatest of which are the Godstones. This article describes the appearance and functioning of the Godstones and provides HârnMaster rules for using them for inter-world travel. This article was originally published in 1990 as part of [ Hârnlore 9] and is a major revision of the "Godstones" article that appeared in [rpgitem=51412, published in 1984.