Line growth

Clark, G. R. (1974), Growth lines in some invertebrate skeletons, Annu. Rev. Earth... 

Clark II, G. R. Mollusk shell Daily growth lines. Science 161, 800-802 (1968). 

Figure 6 Structure of dentine (a) Polished and etched longitndinal section ofacrocodihan tooth, showing the thin onter enamel layer (E) and the growth lines in the inner dentine (D). (b) Oblique section of orthodentine showing the tubules, (c) Oblique section of the orthodentine of a small mammal incisor showing the tubules, (d) Transverse section of the orthodentine of a small mammal tooth showing empty and filled tubules...

Figure 13 Structure of the Scleractinia skeletons (a) Septal growing zone showing the centers of calcification . Diploastrea. (b) Polished and etched section showing the median line of centers of calcification and the outer fibrous layer. Diploastrea. (c) Detail of centers of calcification with their granular structure, and the growth lines in the fibers. Polished and etched section. Lobophyllia. (d) Polished and etched section showing the regular growth lines. Platygyra...

Figure 17 Growth lines (a) Enamel of a dinosanr tooth, (b) Vertical section in a Dinosaur eggshell, (c) Polished and etched section of a fish otolith, (d) Complex structure of a fossil cephalopod shell (Belopterina)...

Otoliths ( earstones ) are small calcified stractmes found in the head of bony fishes. They are an important tool for understanding the life of fish populations. The growth lines and isotopic ratios of otoliths are used to know the migrations of marine fishes, because they are sensitive to salinity and temperatme. Then, the obtained results are helpful to control these parameters in cultivated fishes. In mollusk shells, diseases are usually early diagnosed thanks to shell abnormalities and malformations. These data are then used for fossils and paleoenvironmental reconstractions. 

Striated/striations Surface growth lines parallel or perpendicular to c-axis Chry so beryl... 

If the sides of the crystal are kept straight during growth, the lattice planes remain intact. However, if the crystal is necked-in" or "pulled-in" during growth, line-defects appear in the lattice structure. If this is a laser-crystal that we are growing, the line defects have a localized effect upon the refractive index of the crystal, making it useless as a laser crystal. 

Figure 12.4 Acanthobasiliola doederleini (Davidson), a rhynchonellide. Kei Island, Banda Sea, Indonesia at 345 m ZB3999. (A) The two valve margins at the commissure with ventral spines (above) broken more than the dorsal ones. Centrally the broken, increasingly thick, shell ridge shows from where a new spine grew. On each side, from the margin of the dorsal valve, two spines can be seen with median open and closed sutures on their commissural faces. SEM x 57 (B) detail of spines on opposite sides of the commissure. The two lower dorsal spine bases have thin shell extensions of ventral valve covering their otherwise open bases. The spine suture lines are bordered by V-shaped growth lines. Below these spines the stump of a third displays the smaller diameter of the spine hollow closer to the base of the spine (as in Acanthambonia, Fig. 12. lb). SEM x 90.

USNM 497414. Anterior region of shell (commissure bottom right) showing fine concentric growth lines, and bases of broken spines. SEM x I SO. 

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