Summary: During the summer of 1967 willcmite was found for the first time in the Ilímaussaq alkaline intrusion, South Greenland. The willemite occurs in an albitite together with aegirine/acmite, albite, analcime, arfvedsonite, apatite, chkalovite, hemimorphite, microcline, monazite, natrolite, naujakasite, neptunite, sphalerite, and polylithionite. Analytical, optical, and X-ray data were obtained from the willemite. Willemite from a calcite vein at Franklin Furnace, New Jersey, and from a quartz vein at Mussartût, South Greenland, were also examined.
One of the willemite crystals from Ilimaussaq was a trilling on <101¯0>. This is the first time willemite has been found as a trilling.