These photographs come from a printed catalogue; they are not inspection records. The material name is the catalogue's own wording, not a finding.
Catalogue image, p.168
Catalogue
Catalogue: Osmanlı Kültüründe Tesbih ve Hüsnü Dikeçligil Tesbih Koleksiyonu, 2014, p.168
Fotoğraf: K. H. Tekin, Sabırla Selamete Tane Tane, 2014; yazarın izniyle
Material (catalogue's wording): Mercan
p.168