Thulite

Thulite (rosaline)
Credit: Dave Dyet link

Description

A pale to deep pink translucent Zoisite stone in which manganese replaces up to 2 % of the calcium. Thulite was discovered near Telemark, Norway and named for Thule, an old name for Norway. It has been used as a gemstone and often has streaks of gray or white.

Synonyms and Related terms

zoisite; rosaline

Physical and Chemical Properties

• Cleavage = perfect in one direction
• Luster = vitreous
• Fracture = conchoidal to uneven
• Streak = white or gray
• Fluorescence = inert
• Pleochroism = present; and possibly dichroism or trichroism depending on color

Mohs Hardness	6.0 - 6.5
Density	3.1-3.4 g/ml
Refractive index	1.691 - 1.700
Birefringence	0.006 - 0.018

Resources and Citations

• Gem Identification Lab Manual, Gemological Institute of America, 2016.
• Wikipedia Thulite Accessed Dec 2022
• Mineralogy Database: Zoisite