The present invention relates to a solid composition that is especially in the form of a product cast as a stick or in acupel, the said composition having an outer surface, and containing one or more magnetic bodies (1) of non-zero magnetic susceptibility, the said solid composition being characterized in that these magnetic bodies (1) are on at least part of the said outer surface non-randomly oriented in the solid composition so as to form on the said outer surface one or more pattern(s) (5).
