I was absolutely convinced that I would find loads of beautiful rocks to paint on during my vacation in Croatia. But the first 4 days went by and all I found were small pebbles on an artificial beach or specimens that were much too angular and rough. Nothing to paint on.
Then on the 4th day, we went on a trip along a Lim Fjord. Once again in search of the long-awaited objects, I passed a small fisherman’s house, where a rock oyster tasting was taking place for a group of tourists. I did not belong to the group but briefly watched what was happening from a distance. At the time I had no idea that Tony’s Oyster Shack was an insider tip among oyster gourmets. I was about to leave when I discovered a whole mountain of empty Rock Oyster shells.
Suddenly an idea occurred to me: if I can’t find any suitable rocks, why don’t I try to paint on a Rock Oyster? I quickly picked up as many empty shells as I could carry. Let’s see what can be made of it.
What Is An Oyster?
Oysters (Ostreidae) belong to the family of salt-water mollusks (Bivalvia). Oysters grow on rocks in shallow tidal waters of all oceans. Its hard shell actually looks unsavory, but once you crack this hard shell, you get a delicacy that was already praised for its palatability thousands of years ago.
There are over 100 species that differ in size, color, and shape depending on their place of origin. The shell of the oyster consists of two halves that are connected by a hinge and are closed with the help of a sphincter. One of the valves is more arched than the other. With the arched valve in which the mollusk lies, the oyster is anchored to the ground, the flatter valve serves as a lid. When closed, the shell is almost waterproof, so the mollusk can survive and do without water for up to two weeks.
The shells of the oysters are quite thick and usually sharp-edged, which protects the oyster against predators.
The shell consists mainly of calcium carbonate and the protein conchiolin, and is made up of 3 layers:
– the outer layer (periostracum):
is particularly firm, the color can be gray, brownish, or green depending on environmental factors.
– the middle layer (ostracum):
thin and chalky, consists of calcite crystals
– the inner layer (Hypostracum):
is a mother-of-pearl layer, consisting of aragonite
And in this rock-hard casing lives a tender, very delicate mollusk. I won’t be writing much more about this delicacy, but you’ll find a lot of write-ups on the net. I want to focus on the shell.
How To Clean The Rock Oyster Shell And Prepare It For Painting
First of all, I would like to say that under no circumstances should live mussels be removed from their environment. I only use dead shells that I find on the beach. Or in this case, I picked some up from a huge pile of discarded oyster shells right behind the oyster restaurant.
Now, when you find a rock oyster it will certainly not be shiny, but most likely full of sand and mud. The outer shell will have severe bumps from deposits, barnacles, or worm infestation. Certainly not as good a surface to paint as on perfect rock. The inside of the mussel must also be inspected, there could be tissue remnants of the mollusk, that could cause a fishy smell. All of this must be completely removed in order to create a good painting surface, so the finished painting looks really good. It’s less work than it sounds.
Put the oyster shells in a bucket of clear water and let them soak for a few hours. This softens the coarsest dirt. Then rinse them under running water. An old toothbrush can also be used to loosen the sand from the fine grooves and remove tissue remnants and barnacles. A toothpick can also be a useful tool for this.
Soak the shell in vinegar essence. This will remove the outer layer (periostracum). Wash the shell in between under running water to remove the crystals which will appear. Again a toothbrush will be of help to clean fine grooves. After cleaning, the shiny mother-of-pearl is now visible on the inside part of the shell, its surface feels very smooth.
With the help of a sharp knife and sanding paper, you can further smoothen the outside of the shell. Depending on the natural growth of the oyster, grooves will still remain on the outer shell. This is not tragic, on the contrary, if this side is painted, the grooves create a nice relief effect.
Your oyster is now ready to be painted. When painting the mother-of-pearl side, you have to note that it is much smoother than a stone. The paint does not soak in here, it takes a little longer for the paint to dry. The varnish should be applied one day after painting the oyster at the earliest.