Onyx stone or Persian Marble:
onyx is a commercial term and is almost exclusively for Iran.
onyx stone (Persian Marble) or dense calcareous rocks are the result of the suppression of calcium carbonate or aragonite sediments by superconducting strata, with some poor metamorphic effects.
Persian Marble is a precious stone because of its beauty, strength and resistance to fire and erosion. The ancient Persians and Greeks used this stone extensively in their buildings and statues.
Compared to travertine, Marmarit is more widely used for interior and exterior applications because of its higher hardness and lower porosity.
onyx or Persian Marbles have a mosaic texture. Pure Marmarit is white but because of its color minerals such as hematite, limestone, carbon, etc., they are red, light yellow, black, pink, and a combination of other colors.
Persian marbles (Marmarits) or dense limestones are the result of suppression of calcium carbonate or aragonite sediments by superconducting strata, with some poor metamorphic effects.
Onyx stone or Persian Marbles (Marmarits) are also known in Iran as a trade term called Sanandaj.
One of the characteristics of these rocks is their fine or medium grading and their apolitical texture.
Advantages of marble as a rock:
1-Suitable hardness and fire and erosion resistance
2ـ Suitable for floors and stairs and interior views due to its very low porosity
3- Its beauty and variety of colors, especially in Iran
4- Applicable to classic and modern views
5- Ability to abrasion at rock polishing stage and having proper shine
6- Absence of pores
Disadvantages of Onyx stone or Persian Marble (Marmarit) as a stone:
1-High price, especially its white type.
2-Due to the higher density of Persian Marble (higher specific gravity due to the presence of magnesium carbonate) than travertine and also due to modern building principles based on lightweight structures, Persian Marble is less recommended for exterior use.
3-The presence of crack will make it less resistant to frost and reduce the strength of marble.
4- Due to the porosity and impermeability of the filler material, it is stain-able.
5-Exposure to dyed materials changes the color of the texture and can be corrected only by polishing or removing the stone.
6-Color change caused by long-term sun exposure.