Several crystals of kalsilite were synthesized and the structural refinement was carried out to elucidate the structural detail of the pure end-member of the KAlSiO₄. The crystal is hexagonal, P6₃, with a=5,151(5) and c=8.690(8)Å. The structure was refined by the full-matrix least-squares method on the basis of counter measured intensity data. The structure agrees with those of the natural specimen. But it has the same domain structure as alkali-exchanged specimens investigated previously. The oxygen atoms which link tetrahedral atoms forming ditrigonal rings are disordered at two mirror-equivalent sites. The site occupancy ratio of oxygen atoms between these two positions were also refined on the assumption of the existence of domain structures inside the X-ray coherent regions. The final R-value is 0.084 for 373 observed reflections. While the alkali-exchanged specimens give diffuse streaks parallel to the c^* direction corresponding to the structural disorder in the stacking on the (001) plane, the specimens now investigated give sharp diffraction spots along the c^* direction. The ratio of the volumes of the coherent range of domain structure differs from one specimen to another. The structural relation between the two P6₃ domain structures corresponds to the twinning by merohedry after the classification by Friedel.

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The first Korean roquesite is found in chalcopyrite-arsenopyrite-bearing magnetite-scheelite ore from skarn deposit of the Ulsan mine, Republic of Korea, formed by the intrusion of a granitic body of the Bulgugsa Granite Series into an age-unknown limestone. The average of ten microprobe analyses on three grains yields Cu_1.03Fe_0.02Zn_0.01In_1.02S_2.00 (on the basis of S = 2.00). No significant difference is found in the optical properties from known roquesites. X-ray microdiffractometer pattern gives the lines d = 3.04, 2.74, 1.94, 1.66 and 1.591 Å. The lack of the strongest line (d=3.16 Å) may be due to an orientation effect.
It was formed subsequent to the mineralization of magnetite and scheelite under high temperature and steep geothermal gradient conditions coming from the subvolcanic nature of the intrusion, enabling the formation of chalcopyrite–sphalerite solid solution as proved by the occurrence of sphalerite stars in chalcopyrite.

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Attachment of Gandolfi mode is designed to a Weissenberg camera. The attachment is mountable to a universally used single crystal goniometer head and demountable from it. One can take either oscillation and powder pattern photographs from a single crystal mounted on the attachment. To facilitate centering of a specimen, a simple centering stage is designed. Powder patterns have been successfully obtained by using the attachment.

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