Calliostoma zizyphinum

[BubikolRamios]

looking at those:
http://www.schnecken-und-muscheln.de/gal...atidae.htm

But, mine are 1/2 size of those
http://agrozoo.net/jsp/Galery.jsp?p1=|__...n||gibbula

Is that c.z. anyway ?

especialy comparting to this:
http://agrozoo.net/jsp/Galery_one_image....3e24d4ebf2
which  I once figured out it is Osilinus turbinatus

[poseidon]

well, both of your shells are not calliostoma but gibbula. concerning the "green" shells I didn't see well but anyway please check the below diagnostic character :
if the base of shell is concave = gibbula rarilineata
if the base is convex = gibbula divaricata

regarding the "brown" I can just say that for sure is not calliostoma but gibbula. but the shells is very poor ( beached I suppose) to determine exactly the specie.

[wolfi]

Hi,
Trochidae are tricky, sometimes....... . I'm not sure about the first specimen you called "Calliostoma" (on the left side). The second specimen (on the right side) might be Gibbula divaricata (L., 1758) or Gibbula rarilineata (Michaud, 1829).
Sorry  , but personally I don't think your "Osilinus turbinatus" (= Monodonta turbinata) is an Osilius (or Monodonta) species at all. The genus was named Monodonta because of the little dens (a flat tooth) at the columella, which I can't see in your specimens.  Furthermore, the Osilinus species get much larger than your specimens and the general shape of the shell is different (as far as I can see from your pictures).
Please excuse me, but it's often helpful to take a "frontal view" picture from the shells: axis of the shell exactly vertical, opening (= aperture) facing to the camera. Then it's much easier to judge the shape of the whorls, the sutures and the general shape.
For example: frontal view of a shell:

I hope I could help a little bit........ .
Kind regards: wolf 
Edit: sorry, Poseidon, I was too late (it takes too much time for me to write in English  , you are absolutely right. Sorry, again......... .

[BubikolRamios]

... helpful to take a "frontal view"  .....

Yeah, I'm thinking about that for a while now, any tips how to fit shell into that possition, not using glue, having  as less as posssible photoshoping afterwards, ... ?

For example, I cant just put my gibbula-s on black glas and get that kind of shoot.

[wolfi]

Hi,
just a guess: for taking a picture, I mount the specimen on top of a wooden rod/bar (2 or three inches long) by using a bit of modelling clay for fixing the shell exactly in the desired position. The wooden bar is sticking vertically in a hole of a wooden platform covered by black paper. The wooden bar is helpful to get the shell sharp in contrast to the background. Then I use a tripod and the self-timer to avoid camera shake.
I hope you see what I mean, it's not easy for me to explain, sorry  .
Kind regards: wolf

[poseidon]

never mind wolfi, double check meaning sometime double confirmation .

[BubikolRamios]

So, I took that advice and got myself a black modeling clay.

My epirience with simplification: buy yourself black welding glass, the clay does not stick to it and glass can be cleaned with no fuss to perfection.

Put small amout of clay direct on glass, attach shell and voila: Sample image of upper gibbulas.