Grandidierite gemstone is a rare, blue-green nickel borosilicate mineral with a hardness of 7.5 on the Mohs scale. It forms in igneous rocks and their metamorphic equivalents and can be found in small quantities worldwide. It is found in many locations worldwide, usually as an accessory phase. It is typically found as grains or fine crystals associated with alkali feldspar rocks (albite), nepheline syenites, peridotites, and serpentinites. Grandidierite is often attached to other minerals in masses or druses and can form pale blue bulky crystals. The typical form of Grandidierite is a prismatic crystal and typically has perfect basal cleavage. It can also be granular but usually occurs as an aggregate of grains that are interconnected with others to form a rock of different color than the background.
It is a rare beryllium-rich nickel silicate mineral with similar chemical composition and crystal habit to kunisutite. It has an ideal structure, similar to pyroxferropsum. However, it is not as hard or brittle and has perfect basal cleavage.
Benefits of Grandidierite
1. Utilized in gem cutting or carving.
Grandidierite is commonly used to cut or carve in making jewelry and other decorative objects, especially for carving precious stones. Its hardness is 7.5 on the Mohs scale and can withstand being carved with a diamond or corundum-edged saw or even by hand if handled lightly. It’s also used for making special-use tools for various applications because it is highly resistant to abrasion, impact, and corrosion and is not easy to delaminate due to its hardness.
2. Can be used as construction material.
Grandidierite is used in construction materials as construction aggregate or decorative stone. However, it is soft and unsuitable for general construction work due to its softness.
3. Used for insulation material
Grandidierite has a wide range of applications, including thermal insulation and sound absorption applications. Due to its high heat conductivity (1.4×10 W/(m·K)), Grandidierite is often used as thermal insulation against heat or cold. Grandidierite is commonly used as a thermal insulator in buildings and other types of constructions, such as the thermal insulation layer in steel or concrete structures. It is an excellent thermal insulator that allows for a low-temperature microenvironment. It can insulate heat well at low temperatures since Grandidierite has a relatively high density (1.6 g/cm³).
4. Used for biomineralization
Grandidierite has potential applications for biomineralization in living organisms due to its relatively stable nature. It is used as a source of trace elements, including significant quantities of barium and beryllium, both required in biochemical processes.
5. Used for abrasive
Grandidierite can be used as a substitute for synthetic corundum and synthetic diamond abrasives in industry. It is hard but brittle and can be used for continuous operation except when cutting softer materials such as glass by hand or machine.
6. Used for an optical material
Grandidierite has a high refractive index (n = 2.51). It is used in optical materials, such as optical lenses, eyeglasses, etc. Its high refractive index can also be used for the absorption of light in fluorescent lamps and lasers as a material for laser-reaction or resonant frequency conversion fibers.
What Makes Grandidierite Special?
1. Unique composition and crystal habit
Grandidierite is a rare beryllium-rich nickel silicate mineral with similar chemical composition and crystal habit to kunisutite. Its relatively high density, hardness (7.5 on the Mohs scale), perfect basal cleavage, and high refractive index make it ideal for application in all situations where these properties are required. It can be used in many applications due to its unique characteristics, such as jewelry making, structural building materials, and thermal insulators.
2. Surface coatings
By applying chemical or physical treatments, Grandidierite can be used to make thin films, coatings, and bulk materials.
3. Good machinability
Grandidierite is hard (7.5 Mohs) and brittle and thus requires using diamond or corundum-edged saws or even by hand if handled lightly. It is stable, does not lose its crystal structure or cleavage planes, and can be used in cutting and carving.
4. Long-term use time
Grandidierite has long-term use in the industry due to its resistance to abrasion, impact, and corrosion.