it has the formula of CaMgSi2O6. Furthermore, in the "Minerali Collection" journal, diallage is given the following formula: Ca(Mg,Al)(Al,Si,Al2)SiO6. In addition, theodora.com claims the mineral's composition to be the same as diopside's, however the site also says that it sometimes contains magnesium, aluminium and iron molecules, when it is actually similar to augite in composition (thus diallage being a junction between the two minerals). The fact that the journal claims the Mohs scale to be between 5 - 6, with a specific gravity of 3.2 - 3.3, with theodora.com and the Merriam-Webster dictionary stating it has a Mohs of 4 and a gravity of 3.2 - 3.35, adds confusion to the situation. References Pyroxene group Monoclinic minerals Monoclinic crystals