Quartz (Var: Chalcedony)
Kismantoro District, Wonogiri Regency, Central Java Province, Indonesia
A tan-grey chalcedony epimorph after an unknown mineral, though the predecessor once had distinct twinned orthorhombic crystals - aragonite and cerussite are contenders in the debate, but more study is needed to confirm. No original material appears to remain. Banded chalcedony rims visible on the lower portion of the image show alternating ...
© Erin Delventhal