In the kaolin group, there is an iridescent mineral called the nacrite mineral. It is often described as the rarest kaolin polymorph because its availability is limited compared to others in the group. There are many interesting things to learn about this beautiful mineral, not only its properties but also its common uses.
Basic Information of Nacrite
The mineral has a chemical formula of Al2Si2O5(OH)4. Its composition is 39.50% aluminum oxide, 46.55% silicon dioxide, and 13.96% water. The molecular weight of nacrite is 258.16 gm. Data shows that its Mohs hardness scale ranges from 2 to 2.5, meaning that it is approximately as strong as human nails.
Like dickite, nacrite has a monoclinic crystal structure although both of them are not necessarily identical. Nacrite’s crystal comprises two layers and a big beta angle. The two layers are an aluminum octahedral layer and a silica tetrahedral layer. Its c-axis is around 43 Angstroms in dimensions.
Nacrite mineral gained popularity because of its resemblance with the beautiful mother of pearl. It got its name from the French word for that gem, “nacre.” This mineral was first encountered in Saxony, Germany in 1807.
It is believed that the nacrite is only formed through hydrothermal or pneumatolytic processes. This causes nacrite to be not widely available as dickite, which can also be formed in geodes and coal beds.
When encountering nacrite in nature, it is rather difficult to determine whether it is a true nacrite or other impured minerals. Luckily, several modern tests can be done, including:
- Fourier-Transform Infra-Red (FT-IR).
- Thermal gravimetric analysis (TGA)
- Nitrogen adsorption isotherm
- X-Ray diffraction (XRD)
Nacrite receives attention from the general public these days because of its interesting characteristics, which it shares with other minerals in the kaolin or clay category. The interesting characteristics are:
Dispersion can be defined as the separation system of the substance’s particles into the continuous phase of liquid or solid or gas. According to past studies, kaolin minerals’ dispersion can be manipulated by controlling their pH level. This finding is useful in the manufacturing process.
Nacrite mineral, like other clay minerals, has high plasticity. It means that the mineral can endure ruptures and deformation, up to certain degrees, despite receiving finite force. Of course, this depends on the mineral type itself. However, this group of minerals generally performs better than others.
3. Adsorptive Behavior
Clay-based minerals show adsorptive behavior due to their structures. The adsorption can occur physically and chemically. Clay minerals can adsorb organic matter and other substances for various reasons, including high retention quality, low permeability, and large surface area.
An important finding about clay mineral is that it is non-toxic. For millennia, humans have been using various minerals in the clay group to do a lot of things. As such, current researchers are working toward finding more uses for clay, including nacrite, to deal with the deteriorating environment.
Nacrite Mineral Uses
Being the lesser-known mineral in the group, it is understandable that people know very little about nacrite uses. Here are some uses that you ought to know about:
In China, nacrite is commonly considered a gemstone due to its luxurious appearance. People also use the mineral to create artwork, namely porcelain art. The clay quality of nacrite allows people to create art on it without too much difficulty. To create good porcelain, the artist must resource high-grade nacrites, though.
2. Cement Replacement
As people begin to try finding green construction material alternatives, nacrite becomes one possible choice. Like other clays, it can be used in construction due to its strong adhesive property. Scientists are still working on how to modify its characteristics to further suit the demand for this industry.
3. Cosmetic Industry
The cosmetic industry is, without a doubt, one of the fastest-growing industries in the world. Since many people become more aware of the products they put on their bodies, cosmetic companies begin searching for ingredients that are safe to use. Reportedly, clay substances can increase cosmetics’ physicochemical quality.
It seems that there are many things left to explore from the nacrite mineral as the demand for this substance from all around the globe grows. There will be more research done to create derivatives of nacrite for wider consumption.