Emeralds, with their captivating green hue, have been prized gemstones for centuries and are a popular choice for jewelry. Understanding how they might break is important for appreciating their qualities and ensuring their longevity through proper handling and care.
Defining Cleavage and Fracture
In the study of minerals, the terms “cleavage” and “fracture” describe distinct ways a mineral can break. Cleavage refers to a mineral’s tendency to break along smooth, flat, parallel surfaces, known as cleavage planes. These planes represent inherent weaknesses within the mineral’s repeating atomic structure, where chemical bonds are relatively weaker. Minerals like mica, for instance, exhibit perfect cleavage, allowing them to split into thin sheets.
In contrast, fracture describes how a mineral breaks irregularly, not following any specific planes of weakness. This occurs when forces exceed the strength of atomic bonds where no natural weak planes exist. Common fracture types include:
Conchoidal (shell-like curves)
Uneven (rough and irregular)
Splintery (producing sharp elongated points)
Hackly (jagged and sharp)
All minerals exhibit some form of fracture, even if they also possess cleavage.
How Emeralds Break
Emeralds, a variety of the mineral beryl, do not exhibit cleavage. Instead, they primarily break with a conchoidal fracture, forming smooth, curved, shell-like surfaces often displaying concentric ripples. This occurs because the atomic bonds within the emerald’s hexagonal crystal structure are relatively uniform in strength across all directions.
While emeralds are hard, ranking 7.5 to 8 on the Mohs scale, their resistance to breaking is influenced by their fracture tendency. The Mohs scale measures scratch resistance, not a gemstone’s toughness or impact resistance. Despite their hardness, emeralds are brittle, largely due to their conchoidal fracture and common internal features.
Emerald Durability and Care
Emeralds’ inherent brittleness and tendency to fracture make them susceptible to impact damage. Many emeralds contain inclusions, often called “jardin” (French for garden), which are internal features like fractures, trapped minerals, or fluid-filled cavities. These inclusions act as points of weakness, increasing the likelihood of chipping, cracking, or breaking under stress.
Due to these characteristics, emeralds require careful handling and protective jewelry settings. Avoid wearing emerald jewelry during activities that expose it to impacts, such as gardening or exercising. Also avoid sudden temperature changes, harsh chemicals, and ultrasonic cleaners, as these can damage the stone or affect clarity enhancements. Gentle cleaning with warm, mild soapy water and a soft cloth is recommended to maintain their beauty.