Transparent, colourless crystals of datolite are cut for collectors only. A tinge of yellow, green, or white may also be present. Datolite genrally occurs as a massive material, which may contain copper inclusions.

Localities include Austria, Italy, Norway, United States, Germany, and England. The primary source of massive datolite with inclusions is the Lake Superior area of North America.

Chemical Composition: 

Calcium hydroxyborosilicate

Crystal System / Forms: 

Monoclinic

Hardness: 

5

Specific Gravity: 

2.95

Lustre: 

Vitreous

Refractive Index / Birefringence: 

1.62-1.65 / 0.044

Geological Occurrence: 

Austria, Italy, Norway, United States, Germany, and England.

Cuts & Uses: 

Step cut