Throughout our journey into the  world of natural stone, including feasibility and scientific research; we have come across one important geological fact: the marble and the crystal stones are closely related. The metamorphosis of sedimentary rock due to heat, pressure and acidity forms in both marble and crystal. Both are extracted from underground and come in various shapes, sizes and, colour and texture combinations. 

Of the  three major types of natural stone, sedimentary, igneous, metamorphic; both sedimentary and igneous rock can metamorphose into marble or crystal. The similarities that are found in both marble and crystal are breathtaking. Their colour combinations and textures share many similarities as does the hardness and crystallisation in each rock. The images below show the texture and colour combination similarities between our Jasmine Black and the Obsidian Crystal. 

Jasmine Black Marble

Obsidian Crystal

The hardness of minerals, specifically crystals, is generally determined by the Mohs scale, which was introduced in 1812 by Friedrich Mohs. Mohs, a German geologist, developed a simple procedure to determine the hardness of minerals based on their resistance to scratch. The scale ranges from 1 to 10, 1 being the least hard and 10 being the hardest. Not surprisingly, the hardest mineral on the scale is the diamond. The test is based on the relative hardness of rock types, if a sample mineral can scratch another mineral sample, it is considered relatively hard. 

Due to the similarity between the marble and crystal, Mohs Scale has been used in the natural stone industry for decades. The general understanding in the sector is that natural stone can be categorised based on their hardness. Marble gets 3-5 on the Mohs Scale, whereas Granite gets 6-7 on the scale. While this categorisation provides somewhat general guidelines to taxonomise natural stone, it is not free from drawbacks. Most importantly, the hardness of natural stone shows variation within the same type.  While it is possible to find softer marble that can be carved into statues like the ones used by Italian artists during European Renaissance, the same type of marble can be found in public baths throughout Europe. A well-known sculpture carved by the Italian sculptor Giovanni Strazza shows how Carrara marble can be used so skilfully depicting the intricacies of a veil in natural stone. The same type of marble, on the other hand, is known to be dolomite marble in the stone industry. Dolomite is known to be a harder marble kind.  

Veiled Virgin by Giovanni Strazza early 1850s. 

Although Mohs Scale has been used in the natural industry for decades, we think complementing the natural stone categorisation with the similarities between marble and crystals is essential. Therefore, our stone descriptions at Bamby Stone often start with information about how a marble is related to a crystal and to which crystal. 

Rather than only sticking to the natural categorisation based on Mohs Scale, we have complemented this classification based on the relationship between these two metamorphic formations. The marble and crystal are indeed siblings, as crystals have meanings and can help our minds, bodies and souls, so does the marble. 

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