Diallage is an inosilicate, meaning it's a chain silicate, and is a part of the pyroxene group. Diallage is a junction between augite and diopside, just like fassaite. It was named in 1801 by René Just Haüy. Its name derives from the Greek word diallaghé (meaning change, transform, difference), as its composition differs from that of the other minerals in the pyroxene group. It is a fairly common mineral, and is cheap. Properties Diallage is typically an opaque mineral, but translucent specimens can occur. This mineral forms tabular crystals, meaning the crystals are flatter, and slightly longer than wide. These crystals occur as lamellar masses, meaning the crystals stack on top of each other, and form big chunks. It is a heavy, hard mineral, however, it is fragile. It is not soluble in any acid. According to the Von Kobell-scale, its melting point is high, though the exact melting point of said mineral is not specified. Due to alteration, diallage can grow spots on its surface, which are made out of smaragdite (the green variety of amphibole). It is not surprising, due to both minerals being inosilicates. This alteration is caused by metamorphosis. The spots can also be caused by uralite, another variety of amphibole, as both of them are an alteration product of the diallage. This mineral can also be found interlaminated with bronzite as well, other than smaragdite and uralite. The metallic luster of the mineral is due to something known as schillerization, where diallage goes under an alteration which makes it earn its metallic luster it is known of. When the crystal forms, there are secondary minerals, which are hydrated oxides, such as opal, goethite and limonite. These become microscopic inclusions as diallage grows over the secondary minerals, and these minerals partly or fully fill the cavities. Thanks to these minute inclusions, the mineral reflects the light so that it creates a metallic luster, or the effect commonly known as "schiller". Identification If inspected without the use of tools, it is easy to confuse diallage with other members of both the orthopyroxenes and the clinopyroxenes. For example, metalloidal diallage can easily be confused with hypersthene (hence the pseudohyperstene being diallage's synonym), however it is easy to distinguish them apart just by looking at its optical properties, its luster and its cleavage. Without having proper equipment, diallage could be distinguished from other members of the class due to