Sunstone

Also known as
  • Adventurine Feldspar
  • Aventurine Feldspar
  • Aventurine Orthoclase
  • +2 more

Where it forms, where it's found

37recorded occurrences
Source · OpenStreetMap

Physical

Colour
red · red–green bicolored · and green

The color variations observed in the ten samples are attributed to absorption bands around 560–590 nm, which are caused by the localized surface plasmon resonance of copper nanoparticles with different size and morphology. From the perspective of inclusions, the distribution of dot-like inclusions on the shallow surface of the samples (aggregated into linear, feather-like, or clustered formations) may serve as identifying evidence of copper diffusion treatment.[[1]]

Optical

UV response
The fluorescence spectra of the labradorite and andesine feldspar before and after copper diffusion. The strong fluorescence (under 320 nm excitation) was verified as the key evidence of copper diffusion treatment. The strong fluorescence is attributed to residual Cu+ ions within the feldspar lattice resulting from copper diffusion treatment. During the copper diffusion treatment of labradorite or andesine feldspar, elemental copper diffuses into the crystal lattice via Cu+–Na+ ion exchange. Once inside the crystal lattice, Cu+ ions capture electrons and are subsequently reduced to Cu0, which then aggregates to form copper nanoparticles. Throughout this process, a significant portion of the Cu+ ions may not be reduced to Cu0, thereby exhibiting strong fluorescence under 320 nm UV excitation. They exhibit relatively strong purple fluorescence under 320 nm UV light irradiation.[[1]]

Synonyms

  • Adventurine Feldspar
  • Aventurine Feldspar
  • Aventurine Orthoclase
  • Heliolite
  • Sonnenstein

Literature, links & citation

Citations
  1. 1978Copley, P. A., Gay, P. (1978) A scanning electron microscope investigation of some Norwegian aventurine feldspars. Norsk Geologisk Tidsskrift [Norwegian Journal of Geology], 58 (1) 93-95
  2. 2018Liu, Jia, Shen, Andy H., Zhang, Zhiqing, Wang, Chengsi, Shao, Tian (2018) Revisiting Rainbow Lattice Sunstone from the Harts Range, Australia. The Journal of Gemmology, 36 (1) 44-52 doi:10.15506/jog.2018.36.1.44DOI: 10.15506/jog.2018.36.1.44
  3. 2022Jin, Shiyun; Sun, Ziyin; Palke, Aaron C. (2022) Iron oxide inclusions and exsolution textures of rainbow lattice sunstone. European Journal of Mineralogy, 34 (2). 183-200 doi:10.5194/ejm-34-183-2022DOI: 10.5194/ejm-34-183-2022
  4. 2024Shang, Zhongyi, Zhang, Zhiqing, Zhou, Qingchao (2024) Identification of Some Gem-Quality Red and Green Feldspars. Crystals, 14 (5). 409 doi:10.3390/cryst14050409DOI: 10.3390/cryst14050409
  5. 2025Wang, Chengsi, Shen, Andy H, Heaney, Peter J, Palke, Aaron, Wang, Ke, Wang, Haiying, Kiefert, Lore, Grew, Edward S (2025) Cu nanoparticle geometry as the key to bicolor behavior in Oregon sunstones: An application of LSPR theory in nanomineralogy. American Mineralogist, 110 (2). 293-305
Cite this entry
@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Sunstone — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/sunstone-10984},
  note      = {Accessed 2026-05-11}
}