Restite
Restite is a relatively rare mineral belonging to the garnet group. Its chemical formula is (Mg,Fe)3(Al,Si)2Si3O12. It is essentially a magnesium-iron aluminum silicate garnet. Restite is named after Resti, Italy, where it was first discovered.
Properties:
Restite, like other garnets, forms isometric crystals, typically dodecahedral or trapezohedral. It is usually found in metamorphic rocks. Identifying restite requires careful chemical analysis, as its physical properties can overlap with other garnet species. Its color varies and is not a definitive characteristic for identification. The luster is vitreous to resinous. It exhibits a hardness of approximately 6.5 to 7.5 on the Mohs scale and has a specific gravity that varies depending on its composition.
Occurrence:
Restite typically occurs in metamorphic rocks that have undergone high-pressure, high-temperature conditions. It is often found in eclogites and granulites. Aside from its type locality in Italy, it has been reported in other regions globally, although its precise distribution is not widely documented due to its rarity and the difficulty in distinguishing it from other garnet species without detailed chemical analysis.
Identification:
Due to its variable composition and similarities to other garnets, restite identification usually relies on advanced analytical techniques such as electron microprobe analysis or X-ray diffraction. These methods are necessary to determine the precise chemical composition and crystal structure, allowing for definitive identification.