lonsdaleite

Lonsdaleite is a hexagonal allotrope of carbon, also known as hexagonal diamond. It is similar to the more common cubic diamond but has a different crystal structure. Lonsdaleite is often found in meteorites and is thought to be formed during the high-pressure, high-temperature impact events that create them. It can also be synthesized in laboratories.

The mineral was named after British crystallographer Kathleen Lonsdale, who was the first person to study its crystal structure using X-ray diffraction. Lonsdaleite is significantly harder than regular diamond, although this is still a subject of scientific debate and depends on the purity and structural integrity of the sample. Its optical and electrical properties also differ from cubic diamond, making it a material of interest for various scientific and technological applications.

Despite its extreme hardness, lonsdaleite is rare and typically occurs in microscopic quantities, often intergrown with other forms of carbon. Its formation in meteorites suggests it is a product of astrophysical processes. Research continues to explore methods for producing larger quantities of pure lonsdaleite and to fully understand its unique properties.