Re: raspberry leaf tannins (uhm, opals)
Ah yes, it's the silica, of course!
opals from nettles? oh I love it. :-)
http://www.answersingenesis.org/creation/v12/i1/opals.asp
Vital creationist research
This again is a revolutionary idea, but as before Len has the proof in the bottles in his laboratory. He has opal growing where he initially mixed various dyes to make the solutions black. Sure enough, there sits a black liquid on top of a growing layer of pure clear opal. But in another jar the liquid is clear and the opal is black. Len maintains that every black opal in Lightning Ridge (and 98 per cent of the world’s black opal comes from Lightning Ridge) was originally white—he has seen white opals turn black in his bottles. So much for the old theory that the colours are produced by impurities!
All this sounds exciting but, as always, there is a catch. Len has proved that good stable natural opal hardens while still underwater, because his opal is slowly doing the same. But he hasn’t so far waited the few years or decade necessary for completion of the process to be able to pour the water off his opal and cut it. Instead, he has siphoned the water off through a small hole in the plastic top over his jar and allowed the opal to slowly dry out over a number of months. And here is the ‘catch’. The forced drying caused the opal to crack. Len is working on this problem but has not solved it yet.
wow. I think I've been bitten.
And there's a message in the flax too ... hmmm.