Coral or alga??? with clues... ¡¡¡sea whip or gorgonian fossil !!!

A gorgonian, also known as sea whip or sea fan, is an order of sessile colonial cnidarianfound throughout the oceans of the world, especially in the tropics and subtropics. 

Is like a Venusin vejar coral, a calciumless fossil coral. I founded this stone walking by a mine in a triasic zone.

Nowadays Venusin vejar coral.

Orbicella fossil

Orbicella astraea.

Anthozoa. Pliocene. Diameter: Polypus 9 mm. Spain.

reference picture:

http://www.sil.si.edu/ImageGalaxy/imageGalaxy_enlarge.cfm?id_image=1836

Rock#14 Dolomite crystal?

Its chemical formula is: CaMg(CO₃)₂

Another dolomite stones (for comparison):

http://mineralia.iespana.es/fotos/300/d/dolomita+ojos_negros_(teruel)+4x4+300+20021101v.jpg

http://usuarios.multimania.es/mineralesespana/TeruelDolomita_OjosNegros1.JPG