Hematite is a widely known iron oxide mineral, recognized for its striking metallic gray or black appearance. This metallic resemblance often leads people to mistake it for metal and assume it possesses high durability. However, hematite is a mineral with a distinct crystalline structure, meaning its strength is governed by geological properties. Understanding the difference between its surface hardness and its internal resistance to impact is necessary to gauge its true fragility.
Physical Properties Governing Durability
Hematite’s durability depends on distinguishing between its scratch resistance and its impact resistance. Hematite registers a value between 5 and 6.5 on the Mohs scale of hardness, placing it in a moderate range. This hardness means hematite can resist scratching from many household objects. However, it is softer than common quartz dust, which is a factor in long-term surface degradation.
The mineral’s susceptibility to breaking is determined by how it fractures under stress. Hematite does not possess true cleavage, the tendency to break along smooth, flat planes. Instead, when hematite receives a sharp blow, it exhibits an uneven or subconchoidal fracture. This breakage pattern means the material is brittle and prone to chipping or shattering when subjected to sudden, intense force, such as being dropped. The moderate hardness allows it to withstand abrasion better than softer materials, but its inherent brittleness makes it vulnerable to structural failure from impact.
Vulnerability to External Factors
Beyond the risk of immediate breakage, hematite’s composition as an iron oxide makes it susceptible to degradation from environmental elements. The presence of iron means that prolonged exposure to moisture can lead to surface discoloration or tarnish. Continuous contact with water, especially saltwater or highly acidic sweat, should be avoided to prevent this reddish-brown surface change.
Because hematite is significantly softer than the common mineral components of dust and sand, repeated abrasive action will eventually scratch its polished surface. Storing hematite jewelry or specimens loosely with harder stones will result in the loss of its mirror-like luster over time. Although hematite is thermally stable, rapid or extreme heating can alter its structural integrity and color. It is also vulnerable to strong chemical agents, so harsh cleaning solutions should never be used on the material.
Handling and Maintenance Recommendations
Proper handling is necessary to maintain hematite’s structural integrity and its polished appearance. Due to its brittleness and tendency toward conchoidal fracture, pieces should never be worn during activities that involve a risk of hard impact. To prevent scratching and abrasion, hematite items should be stored separately from other jewelry, particularly pieces containing harder stones such as diamonds, sapphires, or quartz.
When cleaning the mineral, the best method is to use only mild soap and lukewarm water, followed immediately by thorough drying with a soft cloth. It is important to avoid prolonged soaking in water due to the iron content. Highly vibrating cleaning devices, such as ultrasonic cleaners, should not be used as the vibrations can exploit the material’s inherent brittleness, increasing the risk of chipping or shattering.