Plated hematite refers to natural hematite that has been coated with a thin layer of another material. This process alters its surface appearance, often enhancing its luster or introducing new colors.
Understanding Natural Hematite
Natural hematite is a common mineral composed primarily of iron oxide, with the chemical formula Fe2O3. It typically contains about 70% iron and 30% oxygen by weight. The appearance of natural hematite varies, ranging from a shiny metallic gray or silver-black to reddish-brown or dull red forms. When scratched across an unglazed porcelain surface, all varieties of hematite produce a distinctive reddish-brown streak, regardless of their external color.
Natural hematite is known for its density, possessing a specific gravity of approximately 5.3, which makes it feel heavier than many other stones of similar size. While some natural hematite may exhibit very weak magnetic properties, it is generally considered non-magnetic. Its hardness ranges from 5 to 6.5 on the Mohs scale, indicating a moderate resistance to scratching.
The Plating Process
Plating involves applying a thin, decorative coating to the surface of natural hematite. This treatment aims to enhance the stone’s visual appeal, creating a variety of finishes beyond its natural metallic sheen. Common plating materials include titanium or other metals, which can produce vibrant, iridescent, or “rainbow” effects. Electroplating is one method used to achieve these surface modifications.
Plating can create specific aesthetic outcomes, such as a lustrous black or gunmetal finish, often achieved with tin and nickel carbonate coatings. Some plating processes also impart strong magnetic properties to the hematite, resulting in what is frequently sold as “magnetic hematite”. It is important to note that this plating is a surface application and does not change the core composition of the underlying hematite mineral.
Identifying and Caring for Plated Hematite
Unnaturally vibrant colors, such as bright blues, golds, or iridescent rainbow hues, are strong indicators of plating, as natural hematite does not typically display such intense coloration. Over time, the plating may chip, flake, or wear off, revealing the underlying gray or black color of the natural stone. Additionally, if a hematite piece is strongly magnetic, it is likely either plated to achieve this effect or is a man-made material known as “Hematine” or “Hemalyke,” which mimics hematite but is inherently magnetic.
Avoid exposing plated hematite to harsh chemicals, excessive moisture, or abrasive cleaning materials. Cleaning should be done gently using a soft, damp cloth and mild soap, followed by immediate drying to prevent tarnishing or damage to the plating. Storing plated hematite jewelry separately from other items can also help prevent scratches and preserve its surface integrity. The plating can wear off with regular use, especially on high-contact areas.