Bold title, eh?! But it's true in so far as I can ascertain.
J R da Silva worked for the Casa da Moeda do Brasil in the 1960s and 1970s. The current SG catalogue includes two stamps engraved by Da Silva. The first one is the 1969 issue to mark the birth centenary of General Tasso Fragoso.
The second issue also dates from 1969. It is a single stamp issued to mark the birth anniversary of the German immigrant leader Dr. Herman Blumenau.
And that's it.
Luckily for us who always like more, Da Silva also engraved a test stamp in 1975, depicting a sailing ship.
The nature of test stamps is that they are used for testing presses, inks and the like, so you'll normally find them in a number of variying types. So too with this stamp. I managed to get hold of a little selection of six copies, which includes printings of the engraved bits only, either in monochrome or bicoloured. Together, they make quite a nice little collection.
But basically, that was all I could find. I've been searching the internet for a whole week (well, amongst doing many other things, but still) but no result whatsoever. Not a date of birth, no explanation as to why SG writes Da Silva, whereas the credits on the stamps just read Silva, not even a full first name, nada.
So if you happen to know anything about this engraver, I'd be more than happy to hear from you!