u/Familiar-Training-83

Found this on the bottom of the Berzdorfer See near Görlitz, eastern Germany. The lake is a former open-cast lignite (brown coal) mine that was flooded after it closed. The lignite there is Miocene, so the whole pit is basically the remains of an ancient swamp forest — the coal itself is fossilized vegetation.

That’s what makes me suspect this is petrified wood: it came out of the same deposit that produced the coal, it has a strong woody grain running through it, and it scratches glass easily, so it feels mineralized/silicified rather than soft.

Am I right that this is petrified wood, or could it be something else? Thanks!

Found this myself on the bottom of the Berzdorfer See near Görlitz, in eastern Saxony, Germany. The lake is the flooded remnant of the Berzdorf open-cast lignite (brown coal) mine, which operated until 1997 before being flooded. The lignite there is Miocene, so I’m assuming this is a fossil wood fragment from the same ancient swamp forest that formed the coal — roughly 15–20 million years old.

It’s a hand-sized elongated fragment6cm long with strong longitudinal wood grain still clearly visible. Color is olive green with orange/brown iron staining and some darker, more carbonized (lignite-like) zones — looks like the piece preserves both silicified and partly coalified material.

Tests I’ve done so far:

**•	Hardness:** it scratches glass easily and “bites” into it, so I’m reading it as \~7 → silicified (chalcedony/opal range), not the soft coalified type.

**•	Luster:** waxy to vitreous, especially when wet.

**•	Macro photos:** under magnification I can see parallel fiber and aligned pores along the grain, but the surface is rough/unpolished so I can’t resolve individual cells well. I’m seeing the longitudinal view, not a clean transverse section.

A couple of questions for the group:

**1.**	Does this read as silicified fossil wood to you, or could part of it be something else?

**2.**	The Miocene Lusatian lignite swamp forests were dominated by swamp-cypress relatives (Taxodium / Glyptostrobus), and the common fossil wood from these deposits is classified as *Taxodioxylon*. Any chance to confirm conifer vs. hardwood from these photos, or would I need a sanded transverse face / thin section?