Baddeleyite is a rare, naturally-occurring form of zirconium dioxide, or zirconia, which can occasionally be encountered as a collector’s mineral but is almost never faceted. While some baddeleyite crystals are light yellowish and/or brownish, or even colorless, the mineral tends to be most commonly associated with a very dark brownish coloration that verges on black. These stones may also possess a distinctive submetallic lustre, and are generally opaque when not cut into thin slices.

First discovered in Sri Lanka by a railroad superintendent called Joseph Baddeley, baddeleyite’s composition is actually identical to that of the well-known synthetic diamond simulant cubic zirconia (CZ). However, the contrasting crystal forms possessed by these two polymorphs give rise to some vastly different visual and physical attributes, including baddeleyite’s significantly lower hardness (6.5).

Charateristics of Baddeleyite

  • Hardness: 6.5
  • Crystal system: Monoclinic
  • Locality: Kollonnagam, Rakwana, Ratnapura District, Sabaragamuwa Province, Sri Lanka

History of Baddeleyite

It was named for Joseph Baddeley. The mineral was discovered in Rakwana, Ceylon, now known as Sri Lanka. Baddeley was a superintendent of a railroad project in Rakwana. As redacted by J. J. H. Teall, Director of the British Geological Survey in the early 1900s, Baddeleyite has discovered thanks to the discovery of Geikielite. Baddeley happened to send specimens of several pebbles to the Museum of Practical Geology in London, where Mr. Pringle examined them and attempted to classify them. According to Teall, the specimens were submitted to him by Pringle after he failed to assign them and compare them to other species, such as spinel, ilmenite, and so on. After analyzing the specimens, Teall concluded that the mineral was mainly composed of titanic acid and magnesia, with a very small percentage of protoxide of iron. Geikielite has the composition of MgTiO3. Concluding the various analyses, Teall and Pringle decided to name the new mineral Geikielite, taking the name after the Director-General of the Geological Survey, Sir Archibald Geikie. Baddeley then decided to send more specimens to Teall in order to determine a proper specimen to be put in display at the Museum of Practical Geology. While trying to find the best specimen for display, as Teall relates, he noticed that one of the specimens was different from the rest. This new mineral as described was black in color, with a submetallic lustre and a hardness of 6.5. After analyzing the mineral, it was determined that its composition was not MgTiO3, as geikielite’s, but it was ZrO2. Teall proposed that the new mineral should be named baddeleyite, after Joseph Baddeley to honor the man who brought two new minerals to notice.