Identification of white efflorescence on wooden African objects

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Publication Type:

Journal Article


Poulin, Jennifer; Dignard, Carole; Helwig, Kate;


Studies in Conservation, Volume 59, Number 2, p.69-78 (2014)


This article describes the investigation of white efflorescence on eight wooden African objects from Malawi and Zambia and the treatment of the objects to remove the deposits. The source of the efflorescence on these objects was determined to be the heartwood from which they were carved. Using gas chromatography-mass spectrometry and Fourier transform infrared spectrometry, the crystalline efflorescence was found to consist of homopterocarpin and pterocarpin, two isoflavonoid compounds found in woods and shrubs belonging to the genus Pterocarpus, and African Baphida nitida. The crystal growth appeared to be heaviest on areas of the objects that were more deeply carved as well as on those objects without a surface finish. The storage conditions of the collection were studied and found to have likely accelerated the rate and extent of the natural movement of the pterocarpan compounds from the interior of the heartwood to the outer surfaces.