UPDATE (Aug 30, 2017): This specimen is now featured on Mineralienatlas Lexicon)
As a supplement to my recent trip to Brechin, Ontario, Malcolm Thornley offered to prep out a complete Greenops widderensis I found last year. The frustrating thing about these trilobites in Arkona is that they tend to be very fragile and flaky, and most times you find just tail pieces or parts of the cephalon. They only very rarely come out nice and whole like this one. You can go through tons of rock for just one half-decent specimen.
Before this received its masterful prep, I gave it a go using my primitive tools - a Dremel engraver and a sewing needle under a magnifying lens. Here is what I ended up with - as far as I would dare with such a specimen:
Ok, so not bad - but far from museum quality. For that, you need the right tools and the expert touch only a seasoned prep-artist can provide.
Malcolm spent a good amount of time with this one, using a Comco abrasion unit at 7 PSI, with dolomite as the abrasion substance through a 320 mesh screen. He worked out all the scuff marks of my Dremel and removed some of the excess matrix. Using a .015 nozzle, Malcolm prepped this using his Nikon scope at a magnification of 14x. Here are some images he provided of the process:
And finally, below, is the finished masterpiece. He used a .010 nozzle, as small as they may come, to get out the grit between all the nooks and crannies. As Malcolm told me, there were no restorations or use of consolidants. The only imperfection is a bit of damage to the pleura on the mid-right side, but beyond that an exquisitely preserved - and now masterfully prepared museum quality trilobite! I am certainly in awe of his skill.
And, just to compare, the top image beside where this bug was before prep, and halfway through the process, just to show the big difference a good prep can make