What Is Odontolite? The Blue Turquoise Lookalike in Antique Jewellery
Some blue cabochons in antique jewellery may look like turquoise but consist of a different material. Odontolite is one historical example. It is associated with fossil dentine and was also marketed under names such as bone turquoise, which can easily cause confusion. The historic brooch investigation SSEF’s 2012 article describes six brooches containing mostly odontolite, along with some actual turquoise and glass. Microscopic examination and Raman analysis helped separate the materials. The finding shows why matching colour across a jewel does not prove matching identity. How odontolite becomes blue Odontolite contains mainly fluorapatite. The article explains that heating can change the state of manganese traces and create a blue appearance. This is different from simply assuming that every turquoise-coloured material is the mineral turquoise. Surface pores, banding and, in some specimens, features associated with ivory structure contributed to the investigation. Such observa...