IDOCRASE
Idocrase (Vesuvianite): Properties, Colors & Formation
Idocrase, also known as vesuvianite, is a complex calcium aluminum silicate mineral found in contact-metamorphic rocks and skarns. It commonly occurs in green, brown, yellow, or other colors and is collected as crystals and occasionally cut as a gemstone.
Table of Contents
Formation and Geological Setting
Vesuvianite commonly forms where hot fluids alter carbonate rocks near igneous intrusions, creating skarns. Its chemical complexity reflects the conditions and elements present during formation.
Properties and Appearance
Vesuvianite often forms tetragonal crystals and has Mohs hardness around 6–7. Luster is vitreous, and color ranges from green and yellow to brown or blue-green. Crystal shape and matrix can help with identification.
Identification and Collecting
Idocrase may resemble garnet, tourmaline, or other silicates. Crystal habit, optical properties, chemistry, and geological setting help distinguish it. The name vesuvianite is widely used in mineral references.
Care and Handling
Clean specimens gently with a soft brush and avoid harsh chemicals. Protect crystal points and store away from harder minerals that may scratch the surface.
Frequently Asked Questions
Can this material be identified by color alone?
No. Color overlaps among minerals and gem materials; use reliable references and appropriate testing when certainty matters.
Is every specimen suitable for jewelry?
No. Durability depends on cleavage, fractures, inclusions, treatments, and setting. Store and wear specimens with appropriate care.
Further Reading & Sources
- Mindat — mineral data and localities.
- Handbook of Mineralogy — technical descriptions.
- Gemological Institute of America — gem education and identification.
- Wikipedia: Vesuvianite — general background and references.