Summary

A review of the inclusions in sapphires from Madagascar (Adranondambo) which have been found to date is contained in Table I. Some of these inclusions are uniquely found in Madagascan (Adranondambo) sapphires and also, according to present knowledge, represent a worldwide novelty (e.g. primary baddeleyite and zirconolite inclusions).

On the other hand, some inclusions, which are often encountered in sapphires from other deposits, have rarely been perceived in the Madagascan material examined by the authors. This, for example, is the case with zircon. Although this mineral was determined by Kiefert et al. (1996) as an inclusion in Madgascan sapphires, it is certainly extremely rare. It is a much more frequent type of inclusion in the sapphires originating from many other localities such as Kashmir, Sri Lanka, and various basaltic deposits.

Dolomite inclusions were not found during our examination, whether in the mother rock nor as inclusions in the sapphires. Such inclusions, however, are very typically found in Mong Hsu rubies, which are formed by metasomatic processes. This demonstrates the very special genetic character of the Skarn deposits in Madagascar (Adranondambo).

Some inclusions, such as various types of Ca-Na-alumosilicates (most probably calcic-scapolite) could not be definitely identified for this present publication. Their identification will have to be confirmed by X-ray analyses as soon as larger crystals can be separated from the sapphire. In one sample, Ca-rich scapolite (meionite) could be identified by SEM-EDS analyses because of its high Cl - concentration and reaction to HCl.

Also, hibonite has not been detected as an inclusion in the Madagascan (Adranondambo) sapphires. This mineral might be expected as inclusion in sapphire as it is a typical mineral of skarn deposits. However, there are some genetic reasons, why this may not be the case, as will be discussed below.