Crystalline mercury sulphide exists in two drastically different polymorphic forms: red chain-like insulator, alpha-HgS, and black tetrahedral narrow-band semiconductor, beta-HgS. Using pulsed neutron and high-energy X-ray diffraction, we have shown recently that these two mercury bonding pattern are present simultaneously in mercury thioarsenate glasses HgS-As2S3 and govern their electronic, thermal and transport properties. Vitreous arsenic sulphide is a 2D glass formed by AsS3/2 pyramids and the maximum fraction of tetrahedral mercury HgS4/4 is about 30 % for the HgS-As2S3 glass system. The question arises whether this fraction will be higher or even predominant for tetrahedral glassy host GeS2. The neutron diffraction studies of (HgS)x(GeS2)1-x glasses, 0 < x < 0.6, will give a definitive answer useful for practical applications of these new promising disordered systems.