Theo (reply w/o spam) schreef
I cut some attractive slices out of a cedar that was being pruned, and
stuck them in a bag to dry slowly. (I assumed, correctly, that this wood
was unlikely to rot or be damaged by bugs on damp storage.) A couple of
years later, they were covered with a fur of beautiful needle-shaped
crystals with little smell or taste.

Any idea what these crystals might be?

P van Rijckevorsel schreef
I have seen them too. Likely they occur in all Cupressaceae with
heartwood. Never got round to looking up what they might be. A quick look in
Hausen yields quinones &al as common in such woods, but this is an
indication only.
PvR

+ + +
According to the book by Frohne & Jensen the wood of Cupressaceae
can have high contents of terpenes, notably Thymol and Carvacrol
PvR