Types of metamorphic stones

All metamorphic rocks are caused by changing pressure and heat from other rocks. The primary stone or mother stone from which a metamorphic rock is called protolith is called protolith, different prototolytes have different mineralogical and chemical compositions, and therefore different minerals are formed in them due to the imposition of metamorphic conditions.

One of the objectives of the study of metamorphic rocks is to identify the type of mother stone and its changes during a progressive metamorphism. In this regard, the most important criterion is the use of metamorphic index minerals, which are formed in a particular rock due to the pressure and heat of the metamorphism. Due to the diversity of sedimentary and igneous rocks and their abundance, it is very difficult to investigate the changes of each rock during metamorphism, so for ease of investigation, different groups of mother stones are introduced and placed in each group of rocks that have almost the same chemical composition. The main groups of maternal stones referred to by various researchers are:

 Lichens, carbonate, mafic and ultramafic rocks. In each group of rocks, with changes in temperature and pressure, different minerals appear and it is necessary to investigate the changes of these rocks in different facies and according to the indicator minerals of each facies.

Since this atlas is written for the use of Iranian students, the facies and stones found in Iran are with greater emphasis. In this section, different groups of rocks in different facies that represent a certain range of heat and pressure, are investigated and introduced their indicator minerals. 

Changes in lichens (plates)

• Lichens in the phanite-pompleite facies
• Lichens in green schist facies
• Lichens in the emphybolite facies
• Lichens in hornblende-hornfels facies
• Lichens in pyroxene hornfels facies

Metamorphosis of sandstones

•  Sandstones in greenschist facies
• Sandstones in amphiolite facies
•  Sandstones in the facies

Metamorphism of carbonate rocks 

• Carbonate rocks in green schist facies
• Carbonate rocks in amphibolite facies
• Carbonate rocks in hornblende hornfels facies
• Carbonate rocks in the pyroxene hornfels facies
• Carbonate rocks in the Sandionite facies

Metamorphosis of Mafic Rocks

• Mafic rocks in zeolite facies
• Mafic stones in pompleite ayte facies
• Mafic stones in green schist facies
• Mafic rocks in amphiolite facies
• Mafic stones in blue schist facies
• Mafic rocks in eklogite facies
• Mafic rocks in the Albite-Epidot Hornfels facies
• Mafic rocks in Hornblande Hornfels facies
• Mafic rocks in pyroxene hornfels facies

Metamorphism of ultramafic rocks

•  Ultra- K rocks in the phanni faciesofte pompel
•  Ultramuffrocks in green schist facies