From left to right is the ferrous sulphate, barberry bark, Brazilwood chips and logwood chips.
The first veneer sample (far left) is copperas on maple/sycamore.This is also the famous 'harewood' used by furniture and marquetry makers in the 17 th century and after. In reality it appears to have a tinge of green but the silvery grey colour predominates. If a sample of sycamore that has a natural base colour of yellow/cream is used it seems to push the resultant colour further towards a green. Very white maple or holly finishes a blue grey.
The next sample is copperas but this time used on dogame (SA boxwood). That gives a dark green, perhaps a little more vibrant than suggested in the photo.
Next on is pear wood in copperas followed by walnut. The strong tannin content of walnut reacts with the copperas to produce a black. Add logwood chips to the solution and the both the pear and walnut will give a stronger black. Dyeing pear black in logwood chips and ferrous sulphate was supposedly the method that Stradivari used to obtain the black of his violin purflings.
It is the two shades of green that I will use in the rosette of my 1863 Torres copy. Hopefully the effect will be similar to the green that Torres used on some of his rosettes.