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Ya’an Green
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Colour:
green, yellow
Green muscovite Ya'an seal stone(Ya'an green)with its vivid green colour has become an important variety of seal stones in recent years.
The results indicate that the green and yellow matrices of “Ya’an Green” are primarily composed of muscovite, with rutile also present in the yellow matrix. In contrast, the white–green samples are mainly composed of quartz, with muscovite as a secondary mineral. Additionally, it was observed that the (004) crystal plane of muscovite exhibits a peak shift to lower 2θ angles, attributed to the substitution of Al3+ by ions with larger radii, such as Ba2+, Cr3+, and Fe2+, leading to an increase in unit cell parameters and a consequent shift in the peak to lower wavenumbers. The main elements of “Ya’an Green” are Al, Si, and K, with minor elements including Na, Fe, and Cr. Furthermore, Mg2+, Ca2+, Ti4+, Cr3+, and Fe2+ in the samples can substitute for Al3+ through isomorphic substitution.
The results indicate that the green and yellow matrices of “Ya’an Green” are primarily composed of muscovite, with rutile also present in the yellow matrix. In contrast, the white–green samples are mainly composed of quartz, with muscovite as a secondary mineral. Additionally, it was observed that the (004) crystal plane of muscovite exhibits a peak shift to lower 2θ angles, attributed to the substitution of Al3+ by ions with larger radii, such as Ba2+, Cr3+, and Fe2+, leading to an increase in unit cell parameters and a consequent shift in the peak to lower wavenumbers. The main elements of “Ya’an Green” are Al, Si, and K, with minor elements including Na, Fe, and Cr. Furthermore, Mg2+, Ca2+, Ti4+, Cr3+, and Fe2+ in the samples can substitute for Al3+ through isomorphic substitution.
Name Encoding
Latin-1:
Ya'an Green
ASCII-7:
Ya'an Green
Unique Identifiers
Mindat ID:
472099
Long-form identifier:
mindat:1:1:472099:3
Physical Properties of Ya’an Green
Colour:
Green, yellow
Comment:
XRD, Raman and electronic microprobe results show that the green parts of the seal stone samples are muscovite, and the yellow impurity minerals are mainly dolomite and pyrite with a small amount of quartz, apatite and rutile. Environmental scanning electron microscope results show that the shape of muscovite is false hexagonal platelet arranged in a disorderly way in three dimensional space. The idiomorphic pyrite, and massive dolomite with perfect cleavage can be seen. Through UV-Vis analysis, it is speculated that the vivid green colour of the "Ya'an green seal stone" is mainly caused by Cr element in muscovite. [[1]]
The ultraviolet–visible spectra display two broad absorption bands at 422 nm and 615 nm, which are caused by Cr3+ transition, indicating that Cr is the chromogenic element responsible for the green color. A correlation was observed between the Cr3+ content and the hue angle h in “Ya’an Green” samples: the higher the Cr3+ content, the closer the hue angle is to 136°, resulting in a darker green color, while lower Cr3+ content leads to a deviation from the dark green hue. [[2]]
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Ya’an Green
mindat.org URL:
https://www.mindat.org/min-472099.html
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References for Ya’an Green
Reference List:
Localities for Ya’an Green
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
Struck out - Mineral was erroneously reported from this locality.
Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
China | |
| Sun et al. (2025) |
