Fig. 2.

Common morphologies of tropical fish-produced carbonate precipitates. (A) Type 1—Ellipsoidal crystallites (size range: < 0.25 to 3 μm long); (B) Type 2—Straw-bundle crystallites (size range: 1–3 μm long); (C) Type 3—Polycrystalline dumbbell-shaped aggregates (size range: typically 1–3 μm long, but large examples to ∼10–15 μm also occur); (D) Type 4—Polycrystalline spheroidal aggregates (size range: < 10 to 30 μm diameter). Occur both as discrete spheres and as multilobate aggregations of spheres; (E) Large polycrystalline aggregates with a semisphere morphology (size range: ∼5 to ∼30 μm diameter); (F) Elongate rod-like crystallites which often occur as intergrown bundles of crystallites (size range: 2–3 μm long); (G) Splayed ellipsoidal crystallites (size range ∼2 μm long and narrow towards their terminal points).