468x60 Ads

Jasper

Jasper is a massive, fine-grained, opaque variety of chalcedony, believed to protect against sight defects and drought. It occurs in shades of brown, greyish blue, red, yellow and green and mixtures of these.

Orbicular jasper has white or grey, eye-shaped patterns surrounded by red jasper. Riband jasper is striped and used in carvings, cameos, and intaglios, which show off its layered structure. Hornstone is a grey variety.

Red jasper occurs in India and Venezuela; various colors occur in United States, especially orbicular jasper in California; red and green riband jasper occurs in Russia. It also occurs in France and Germany.

Jasper Properties

Chemical Composition: 
Silicon dioxide
Crystal System / Forms: 
Trigonal
Hardness: 
7
Specific Gravity: 
2.61
Lustre: 
Vitreous
Refractive Index / Birefringence: 
1.53-1.54 / 0.004
Cuts & Uses: 
Cameo, Polished.