Corundum is not uncommon on Earth but the gem varieties of ruby and sapphire are
relatively rare. Gem corundum deposits are classified as primary and secondary deposits …

The great challenge of geographic origin determination is to connect the properties and
features of individual gems to the geology of their deposits. Similar geologic environments …

Several recent papers have purported to find ultra-reduced minerals—as natural examples—
within ophiolitic mantle sections, including SiC moissanite, Fe-Si alloys, various metal …

A wide number of genetic models have been proposed for volcanically transported ruby and
sapphire deposits around the world. In this contribution we compare the trace element …

Corundum-rich (up to 55 vol.%) felsic dykes formed with albite,±K-feldspar,±hercynite
and±biotite-siderophyllite cut the lower crustal rocks exposed in the Ivrea–Verbano Zone …

Corundum megacrysts from Cenozoic alkaline basaltic fields, notably in eastern Asia and
Australia, are economically important but poorly understood in their genesis. Here we …

Gem-quality zircon megacrysts occur in placer deposits in the Central Highlands, Vietnam,
and have euhedral to anhedral crystal shapes with dimensions of~ 3 cm in length. These …

We appreciate Griffin et al.(2019b) for their quick reaction and comments on our results on
the possibility of the anthropogenic origin of enigmatic corundum with super-reduced (SR) …

In natural corundum, a strong geochemical correlation is sometimes observed between Be
and heavy high field strength elements (HHFSEs) such as Nb, Ta and W, and it has been …

Corundum is rarely found in situ within alkali syenites. A corundum-bearing syenite was
found in the Yushishan rare metal deposits of the eastern section of the Altyn Tagh fault in …