 Another apparent violation that is not regarded as such is the "very uncommon" practice of a bordure of the same tincture of the field being blazoned as "embordured"; while well known in former times this is unusual in the extreme today.How technical the rule is can be seen by the fact that if this were blazoned as "Gules... a bordure of the field...", though of identical appearance, it would be considered a blatant violation.The colours bleu celeste and the U.S. Institute of Heraldry-invented buff have sometimes been treated (with respect to the rule of tincture) as if they are metals, though such a treatment is certainly of debatable propriety.