|
INVESTIGATIONS
|
Stone |
RI min |
RI max |
Dens min |
Dens max |
Colour |
Location |
Info |
Spectrum |
UVS |
UVL |
Reference |
|
Obsidian |
1,469 |
1,469 |
2,36 |
2,36 |
vivid spectrum of colours |
Glass Buttes, Oregon, USA |
fire obsidian |
|
|
|
Gems & Gemology 2023
Summer, p260 |
|
Obsidian |
1,488 |
1,488 |
237 |
2,37 |
black greyish |
|
53.8ct, rainbow obsidian,
cabochon |
|
inert |
inert |
ACAM Lab 2069 |
|
Obsidian |
1,489 |
1,489 |
2,36 |
2,36 |
brown |
Puno, Peru |
Macusanite, transparent |
|
|
|
Zeitschrift der Deutschen
Gemmologischen Gesellschaft 1995 44(1), p25-28 |
|
Obsidian |
1,489 |
1,489 |
2,35 |
2,35 |
dark brown |
|
bright reflective
aventurescence caused by hematite and ilmenite platelets, "star
obsidian" |
|
inert |
inert |
Gems & Gemology 2003
Fall, p233 |
|
Obsidian |
1,54 |
1,54 |
2,36 |
2,36 |
slightly yellowish |
Atacama, Chili |
|
|
|
|
The Journal of Gemmology
1998 Vol 26, N°5,p321-323 |
TABLES
|
Stone |
RI
min |
RI
max |
Dens
min |
Dens
max |
Reference |
|
Obsidian |
1.48 |
1.51 |
2.3 |
2.5 |
John Sinkakas,
Gemstone and mineral data book,1972 |
|
Obsidian |
1.48 |
1.52 |
2.35 |
2.55 |
Bestimmungstabellen
für Edelsteine, Birgit Günther, 1981 |
|
Obsidian |
1.48 |
1.51 |
2.3 |
3 |
http://www.gemmology.be |
|
Obsidian |
1.48 |
1.51 |
2.33 |
2.45 |
Tabellen zur Edelstein-Bestimmung,
Pschichholz FGA, 1975 |
|
Obsidian |
1.48 |
1.51 |
2.33 |
2.42 |
http://www.geminterest.com |
|
Obsidian |
1.48 |
1.51 |
2.33 |
2.42 |
Gems, R Webster,
5th edition 1994 |
|
Obsidian |
1.48 |
1.51 |
2.33 |
2.42 |
Tables of
Gemstone Identification, Roger Dedeyne, Ivo Quintens, 2007 |
|
Obsidian |
1.48 |
1.51 |
2.33 |
2.5 |
Gemology Tools Professional 2010 |
|
Obsidian |
1.48 |
1.51 |
2.3 |
2.6 |
Gemmo.eu
|
|
Obsidian |
1.5 |
1.5 |
2.33 |
2.42 |
Gemme, Dati per l'identificazione, P. De
Stefano et al, 1993 |
|
Obsidian |
|
|
2.33 |
2.42 |
Joel Arem, Color
Encyclopedia of Gemstones, 1987 |
CAUSE OF
COLOUR
MINERAL
INCLUSIONS
|
Inclusion |
Stone |
Reference |
|
spessartine |
Obsidian |
Gems&Gemology 2005, summer p179 |
|
sillimanite |
Obsidian |
Gems&Gemology 2005, summer p179 |
|
indialite |
Obsidian |
Gems&Gemology 2005, summer p179 |
LOCALITIES
|
STONE |
LOCALITIES |
REFERENCE |
|||
|
rainbow obsidian |
|
|
Jalisco |
Mexico |
Gems & Gemology 2001 Spring p71 |
|
obsidian |
Glass Buttes (Obsidian Buttes) |
Lake County |
Oregon |
USA |
Gem Trails of
Oregon, James R. Mitchell 1998 |
CHEMICAL DATA
(%)
|
Stone |
Colour |
Locality |
Reference |
SiO2 |
Al2O3 |
MnO |
MgO |
FeO |
TiO2 |
CaO |
Na2O |
Cr2O3 |
Fe2O3 |
K2O |
P2O5 |
Cl |
SO3 |
|
|
obsidian |
|
|
Mexico |
The Journal of
Gemmology 2000, Vol 27, N°5,p282 |
75.13 |
12.46 |
|
|
|
0.08 |
0.25 |
5.24 |
0.08 |
2.01 |
4.75 |
|
|
|
|
obsidian |
slightly yellowish |
Atacama |
Chili |
The Journal of
Gemmology 1998, Vol 26, N°5,p322 |
74.2 |
14.26 |
0.27 |
0.08 |
0.46 |
0.09 |
0.33 |
4.48 |
|
|
3.82 |
|
|
|
|
obsidian (Macusanite) |
|
|
Peru |
The Journal of
Gemmology 1998, Vol 26, N°5,p322 |
77.98 |
0.54 |
|
|
|
13.16 |
1.34 |
|
|
|
6.98 |
|
|
|
|
obsidian (Macusanite) |
|
|
USA |
The Journal of
Gemmology 1998, Vol 26, N°5,p322 |
74.64 |
12.48 |
0.06 |
0.44 |
0.82 |
0.12 |
2.25 |
5.66 |
|
|
2.46 |
0.24 |
0.25 |
0.58 |
|
obsidian |
|
|
USA |
The Journal of
Gemmology 2000, Vol 27, N°5,p282 |
74.61 |
12.77 |
|
|
|
0.15 |
1.12 |
4.5 |
0.08 |
1.04 |
5.74 |
|
|
|