Ammonite Shell | Gemopedia

Ammonites were marine animals that existed during the Jurassic and Cretaceous periods, and are related to modern-day octopi, squid and cuttlefish. The same event that wiped out dinosaurs was the end of this species, as well. On rare occasions, the ammonite fossilized shells became mineralized, exhibiting a striking iridescent play of color. Ammonite is typically found as fossil specimens or as iridescent gems cut from the fossils under the trade name Ammolite.
Alternate
Names
Ammolite, Ammonite, Korite, Aapaok And Calcentine
Colors
Gray To Brown Sometimes With Iridescent Colors

Ammonite Shell Classification

Common Name

Ammonite Shell

Species

NA

Variety

Colors

Gray To Brown Sometimes With Iridescent Colors

Alternate Names

Ammolite, Ammonite, Korite, Aapaok And Calcentine

Gemstone Groups

Key Separations

Appearance, RI

Comments

Fossilized shell of nautilus like creature.

Ammonite Shell Optical Properties

Transparency

Opaque

Refractive Index

1.52-1.68
Tolerance:varies

Birefringence

0.155

Optic Character

NA

Optic Sign

NA

Polariscope Reaction

Aggregate (AGG)

Fluorescence

SWUV: Inert
LWUV: Inert

CCF Reaction

Pleochroism

None

Dispersion

Comments

Ammonite Shell Chemistry & Crystallography

Chemical Name

Primarily aragonite or calcite; may also contain pyrite, silica and other materials

Chemical Formula

fossilized ammonite shell

Synthesis

Crystal System

NA

Classification

Organic

Nature

Natural

Crystallinity

Comments

Ammonite Shell Characteristic Physical Properties

Hardness

4

Streak

Specific Gravity

2.75-2.8 Typical:2.7

Toughness

Varies

Inclusions

Well preserved specimens show nautilus or spiral like appearance. Rare specimens display iridescence with mosaic patterns. Due the nature of the material it is often stabilized with polymers.

Luster

Vitreous

Stability

Poor

Fracture

Granular, Uneven

Cleavage

None

Comments

JTV on Google+
0 Items
My Wish List
Close
Item
Description
Qty.
Price


Estimated Order Total:
0
Total Due Today:
0
Close
Item
Description
Qty.
Price


Page of 1