Borosilicate: An Important Class Of Minerals

Nov 9, 2022 | Chemistry, SCIENCE

Get to Know Borosilicate and Its Minerals

Borosilicate is an important class of minerals that provides insights into the Earth’s crust and the processes that formed it. Tourmaline is the most common borosilicate mineral, which can be found in many different colors. Other notable members of this class include axinite, werdingite, boralsilite, dumortierite, holtite, howlite, and grandidierite.




Axinite is a class of borosilicate minerals with a similar structure. The word “Axinite” is derived from the Greek word acine, which corresponds to crystals with axe-like shapes. The minerals classified as Axinite are calcium aluminum borosilicate isotopes. 

Different minerals have different names based on their color, richness, and specific gravity. Axinite-Fe, for example, is high in iron and has a brownish color, whereas axinite-Mn is high in manganese and has a yellowish-orange color. 

Axinite can be found in metamorphic rocks, particularly those subjected to contact metamorphism. 

Axinite has a wide range of applications. Some of these minerals are used as gemstones, while others have metaphysical properties and are used in the medical industry. Axinite is also widely used in meditation because it improves accessibility to spiritual universes and higher planes.

This mineral is brittle and tough, with a Mohs hardness of 6-7.5. It has a vitreous luster and is transparent to translucent. 


Werdingite is a borosilicate mineral with the formula (Mg, Fe)2Al14B4Si4O37. It was named after its discoverer, German mineralogist Gunter Werding.

Werdingite is translucent and typically occurs as brownish-yellow crystals with a Mohs hardness of 7 and a specific gravity of 3.04. 

Werdingite has only been found in a few localities worldwide, including Bok se Puts Farm, South Africa.


Boralsilite, with the formula Al16B6O30, is an anhydrous aluminum-borosilicate (Si2O7). It has a vitreous luster and is a white or colorless solid with a density of 3.06. Boralsilite is found in granitic pegmatite splitting granulite-facies metapelite rocks as a tourmaline-quartz. It is structurally similar to sillimanite.

Boralsilite was labeled after its chemical composition, which includes BORon, ALuminum, and SILicon.


Dumortierite is a stunning blue mineral frequently used as a gemstone. It was named after Eugene Dumortier, a French paleontologist who described it for the first time in 1881. Its full name is blue dumortierite quartz, with quartz referring to silica crystals.

Dumortierite is a mineral composed of aluminum borosilicate with the chemical formula Al7BO3(SiO4)3O3. The presence of iron and other trivalent elements for aluminum in the crystal structure causes its color variations. It has a vitreous luster and a Mohs hardness range of 7 to 8.5.

It is found in several countries worldwide, including France, Italy, Austria, Nevada, Poland, Brazil, Russia, Sri Lanka, and Canada.

This beautiful mineral is loved by gem collectors and jewelry designers for its unique blue color. It is sometimes confused with other blue minerals, such as sodalite and lapis lazuli. However, dumortierite is usually darker and is fibrous.

Dumortierite promotes calm, comfort, and harmony and is especially useful where overexcited behavior and stubbornness are required.

It is a reassuring stone that inspires confidence and getting up for oneself while staying faithful to one’s convictions and emotions. It also enables you to recognize the potential in those around you.

Dumortierite stimulates the throat and third eye chakras. It is a communication stone that encourages the verbalization of ideas. It also fosters an understanding of the Universe’s natural order.


Holtite is an orthorhombic borosilicate mineral with the chemical formula Al6(Al, Ta)(SiO4, SbO4, AsO4)3(BO3)O3.

Its hues range from light buff to cream-buff, deep olive-buff, brown, and russet. Holtite has a specific gravity of 3.6-3.9 and a hardness of 8.5 on the Mohs scale.

Harold Edward Holt, Australia’s Prime Minister, inspired the name of this borosilicate, holtite.


Howlite, a type of borosilicate, is a beautiful white stone discovered by Henry How in 1868. It is found in evaporite deposits and is often used in jewelry and other decorative objects.

Howlite has a long history of use. The stone is believed to have healing properties and was used in ceremonies and rituals to promote health and well-being.

Howlite is a calming stone that can help relieve stress and anxiety. It is also said to promote sleep and relaxation and is often used in meditation and healing practices. Howlite also encourages communication and understanding, making it a perfect stone for those seeking clarity in their lives. 

Howlite crystal benefits the crown chakra, the energy center point at the top of the skull. This chakra is associated with wisdom, enlightenment, and spiritual connection. This also promotes peace and harmony within the body.

This beautiful stone is ideal for individuals with a Gemini personality since it restores a desire for adventure and curiosity. Gemini is known for its exceptional ability to appreciate conversation and sensitivity, and howlite is the ideal complement to these characteristics.


Grandidierite is a bluish-green borosilicate discovered in Madagascar and is now the world’s primary source. Along with this, it is also available in Malawi, Namibia, and Sri Lanka. 

Grandidierite was first described in 1902 and named after Alfred Grandidier, a French explorer. It is extremely rare and so is highly prized. 

Grandidierite is primarily composed of magnesium, boron, and aluminum but gets its color from traces of iron content present during its formation. It typically takes the form of tabular crystals that are transparent to translucent. It has a vitreous and glassy luster with a Mohs hardness of 7.5 and a density of 2.976. 

Grandidierite is not just a gemstone but one of the world’s rarest minerals. It has a strong appeal for those searching for something different. 

Grandidierite is occasionally cut into cabochons weighing 1 to 10 carats for use in jewelry. This stone is also said to have several healing properties. For one thing, it’s thought to aid in keeping a healthy heart and blood flow. It is also said to strengthen the wearer’s immune system and aid in healing ailments, including sore throats, tonsillitis, and viral infections.