Steatite

A very soft rock mostly consisting of the mineral Talc., also known as soapstone, is made up of hydrated magnesium silicate. It is simple to cut and has been used for carving since ancient times. Steatite is usually white, greyish green, brown, or, in extreme cases, red or black in colour. Bowls, boxes, and small items such as figurines, beads, seals, amulets, and scarabs were made from stones. Native steatite is so fragile that it can be scratched with a fingernail, but baking causes the stone to dehydrate and harden. Some ancient steatite carvings were glazed and fired, resulting in the formation of a mineral (enstatite) hard enough to scratch glass.

Steatite Formation

Steatite is typically formed at plate convergent boundaries. Periodites, serpentinites, and dunites are metamorphosed into soapstones in these areas of the Earth's crust due to direct pressure and heat. It can also be produced by metasomatism, which is the alteration of dolostones by hot and chemically active fluids.

Composition

Its composition is determined by the parent rock material as well as the temperature/pressure conditions of its metamorphic climate. As a consequence, the physical properties of Steatite can differ from quarry to quarry, and even within a single rock unit. It is mostly talc with traces of chlorite and amphiboles (typically tremolite, anthophyllite, and cummingtonite) and traces of small iron-chromium oxide. It could be either schistose or huge. Metamorphism of ultramafic protoliths (such as dunite or serpentinite) and metasomatism of siliceous dolomites combine to form it.

Pure steatite consists of 63.37% silica, 31.88% magnesia, and 4.74% water. It usually contains smaller quantities of some other oxides like CaO or Al2O3.

Properties

Steatite is a low-cost material with excellent mechanical strength and a very low dielectric loss factor at high temperatures. Because of these characteristics, it is suitable for high frequency, low loss, and high voltage insulation. Furthermore, steatite is an excellent material for electrical engineering since it can be easily shaped into a wide range of shapes such as washers, bushings, resistor types, spaces, and beads.

Uses

We use rock steatite (also known as soapstone) for countertops, sinks, masonry heaters, flooring, and a variety of other architectural applications. Steatite is made up of many minerals, the most common of which is talc. Steatite, because of its additives, is tougher than talc and more ideal for the aforementioned applications. In its initial state, steatite only comes in grey shades, as opposed to talc, which comes in a number of colours.

This naturally quarried stone is softer than most other minerals found in nature. Soapstone, despite its softness, is a very dense (non-porous) stone, denser than marble, slate, limestone, and even granite. Since soapstone is impenetrable, it will not stain and will not allow liquid to permeate its surface. Other stones, such as granite, are prone to soiling, which is why soapstone (steatite) is commonly used in chemistry lab countertops and acid rooms. Steatite has long been used in large-scale industrial processes, consumer electronics, aerospace and automotive applications, and advanced electro-technical instruments such as cathode-ray tubes.

Inlaid patterns, sculpture, coasters, and kitchen countertops and sinks are all made from soapstone. Soapstone is frequently used in traditional Inuit carvings, and some Native American groups made bowls, cooking slabs, and other artefacts from it, especially during the Late Archaic archaeological era. Soapstone is often used for fireplace surrounds and woodstoves because it absorbs and distributes heat evenly while being simple to make. This is a popular feature in many upscale Alaskan homes. Griddles and other cookware are also made from it. Soapstone has been used as a soft medium for carving in India for decades, but global demand for soapstone is threatening the habitat of India's tigers. Soapstone was used to construct the temples of the Hoysala Empire.

Steatite Manufacturing at Harappa

Steatite (soapstone) objects have been discovered at almost every excavated Harappan (2600-1900 BC) site and were also primary elements used to make seals. The Indus peoples used valuable ornaments and decorations made of steatite and faience as symbols of status and prosperity. The seals and tablets were even more significant because elites used them to legitimise and strengthen their political, economic, and ritual influence. Because of the importance of these artefacts to the Indus people, it is important to understand who was in charge of their production and how they were produced.

Overview of Applications

• Heating factor supports

• Insulators for electricals

• Stand-off insulators 

• Insulators for lighting (supports, bases, etc.)

• Spacers

• Insulating washers for bushings

Conclusion

Steatite is a magnesium silicate composite that has been used as an insulator or enclosure for electrical components for several decades. It has also been used in a variety of appliance, aerospace, and automotive applications where moderate power, low cost, and good electrical resistance are needed. Since this ceramic material can be moulded into complex shapes prior to sintering, it has found widespread use in a wide range of applications. In addition to the traditional formulation, the substance is also available in a Low Loss and White version.