Spessartine Spessartine Spessartine, sometimes mistakenly referred to as spessartite, is a nesosilicate, manganese aluminium garnet species, MnAl(SiO). The mineral spessartine should not be confused with a type of igneous rock (a lamprophyre) called spessartite. Spessartine's name is a derivative of Spessart in Bavaria, Germany, the type locality of the mineral. It occurs most often in granite pegmatite and allied rock types and in certain low-grade metamorphic phyllites. Sources include Australia, Myanmar, India, Afghanistan, Israel, Madagascar, Namibia, Nigeria, Mozambique, Tanzania and the United States. Spessartine of an orange-yellow has been called "Mandarin garnet" and is found in Madagascar. Violet-red spessartines are found
Gemstone irradiation for 16 months, the previously colorless diamond became green. This method produced a dangerously high degree of long-term residual radioactivity and is no longer in use. However, radium-treated green diamonds are still occasionally found in markets, which can be detected by a Geiger counter or by making autoradiographs on photographic films. The concerns for possible health risks related to the residual radioactivity of the gemstones led to government regulations in many countries. In the United States, the Nuclear Regulatory Commission (NRC) has set strict limits on the allowable levels of residual radioactivity before an irradiated gemstone can be distributed in