Petrified Wood – Xinjiang, China
Contributed by: Michael Crawford
Date: Apr 18th, 2026
Locality: Xinjiang, China (See on Mindat)
Size: 12.5 x 17 cm
Description:
This is a slab of petrified wood from Xinjiang Province, China. It is a Jurassic age conifer. The wood has been replaced by chalcedony and calcite. The first image shows the fluorescent response from MW illumination. The chalcedony fluoresces brown and green. The brown fluorescence is likely activated by organics, and the green fluorescence is activated by trace amount of uranyl ions. The calcite has an unusual fluorescent color (violet blue) that looks like fluorescent fluorite. However, the mineral is strongly reactive to a drop of acid typical of calcite. The LW fluorescence of this calcite is a dull white color, whereas the violet blue fluorescence of fluorite is brightest in LW. The violet-blue of this calcite fluorescence is brightest in MW. Under SW, the chalcedony fluoresces green and the calcite is a dimmer violet blue.
Summary of luminescence responses:
Calcite (Mindat) (RRUFF)
- Fluorescence under Midwave (305nm LED) UV light: Blue
- Fluorescence under Shortwave (255nm LED) UV light: Green
- Fluorescence under Midwave (305nm LED) UV light: Green
- Fluorescence under Midwave (305nm LED) UV light: Yellow
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Green