👉 Tephroite is a type of mineral in which a mineral (usually quartz) has been converted into an organic substance. This process can occur when the mineral is heated or subjected to other conditions that cause it to undergo chemical changes, resulting in the formation of a new mineral. For example, in the case of tephra, a layer of sandstone or limestone that is formed as a result of volcanic activity and subsequent weathering, the tephroite is an organic matter that has
