(via Wahroongai News, Volume 30, May 1996) Grahame Brown writes:
Myrrh, one of the three gifts to the baby Jesus by the three wise men of the Bible, is an aromatic resin produced by the desert tree Commiphora myrrha. In Western Africa the hardened resin from this tree has been hand shaped into beads to be worn for decorative or other purposes.
As determined by Robert Kammerling, and described in the Fall 95 issue of Gems & Gemology (p.210), this very rare biological gem material has the following properties.
Hardness: scratched with fingernail (<2½)
Fracture: granular
Color: yellowish brown to brown
Diaphenity: translucent
Specific gravity: 1.27
Spot refractive index: 1.40
Fluorescence: LW UV (moderate, even, chalky yellow); SW UV (weak, even, chalky yellow)
Absorption spectrum (visible): cut off at 430nm
Absorption spectrum (infrared): broad peaks at 5180, 4778, 4000 cm ¯¹, sharp peaks at 4339 and 4252 cm ¯¹
Thermal stability: readily melts
Characteristic odor: sweet and spicy odor following abrasion and / or rubbing.
No comments:
Post a Comment