605 - I.G. Farben, “Igmerald”, synthetic emerald in emerald cut, promotional case, probably 1935 to 1942

I.G. Farben, “Igmerald”, synthetic emerald in emerald cut, promotional case, probably 1935 to 1942 Synthetic emerald in a case. Promotional item of I.G. Farben, small book-shaped hinged case, covered in red with a grained surface, the front with a gold-coloured emblem “i” and “G” in a circle, tab closure with red button; inside the lid a label inscribed “»IGMARALD«”, “der synthetische Smaragd der »I. G.«” and “PROF. K. B. BERTHOLD”; in the lower part a stone compartment with gold-coloured frame lines and a small flap, holding on a light cushion the stone of 1.95 ct in emerald cut (octagonal step cut). Condition very good commensurate with age. 6x6x2 cm (LxWxD) The “Igmerald”, named after the initials “I.G.” and the English word emerald, is the synthetic emerald grown by I.G. Farbenindustrie at its Bitterfeld works using the flux process developed by Hermann Espig. Presented to the public in mid-1935, the stone was produced in small numbers until 1942; the chemical group did not pursue commercial production, and the stones were never sold through the trade. Richard Nacken had already grown the first facetable synthetic emeralds in the mid-1920s; the “Igmerald” reached commercial stone sizes and is a subject of the gemmological literature on gem synthesis. Prof. K. B. Berthold is probably the goldsmith Karl Berthold (1889 to 1975), who taught at the Staatliche Zeichenakademie in Hanau and headed the Kölner Werkschulen from 1933 to 1945. Literature: K. Schmetzer and L. Kiefert, Zur Färbung von Igmerald (synthetischer Smaragd, hergestellt von der I.G. Farbenindustrie), 1998.