I found Harn in the fall of 1983, and subsequently discovered this fascinating idea of ancient ruins built by a long-forgotten race. The ruins generally are called Earthmaster sites, and almost all have an odd material they are made of. I instantly wanted to incorporate this idea into my Castle, but wasn't sure how it would fit into the overall theme, and more importantly, why it would exist.
It wasn't until I happened across a discussion at Gencon in the Summer of 84 that the final pieces fell into place. This material known as Pseudostone, which is what the Earthmaster sites are made of, could serve as a conduit of a sort, and fuel TCotBO's main structure.
From Columbia Games website page on Godstones, this snippet gives a fair understanding of them:
Of all the enigmas in the Kethrian family of worlds, none is more puzzling than that of the Earthmasters, who appeared from nowhere some 20,000 years ago then five millennia later disappeared as suddenly. 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.
Godstone is a misleading term. While most people respect and fear Godstones, few actually worship them. Their name is rich in the tradition of times when they were attributed to the gods and, therefore, deemed proper objects of veneration. Among the common folk, "Godstone" remains the most popular name.
The typical Godstone is a monolith, ten feet high, five feet by three at the base and four feet by three at the top. Godstones are made of a grayish, featureless stone-like material called pseudostone, a material commonly used in Earthmaster construction. Pseudostone is impervious to physical harm and seems to have no temperature at all.
So I set about to build a multi-level structure, long forgotten to the ravages of time, and had the Motte & Bailey substructure built onto a connecting passageway. While work took place over Thanksgiving of 1984, I didn't finalize it till a week later.
The Vargas Earthmaster site: