Ammonite

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Refractive Index : 1.680 – 1.520

Optical Characteristic : AGG

Specific Gravity : 2.85 – 2.60 (usually about 2.70)-varies with mineral content

Chemical composition : Often Variable, usually aragonite, calcite, pyrite, silica and more

Crystal System : Organic

Variety/Species : None

Species/Group : Ammonite

Birefringence : 0.155 (varies)

Dispersion : None

Hardness : 4.5 to 5.5

Toughness : Fair to poor

Ultrasonic : Never

Steam : Never

UV Long : Variable

UV Short : Variable

Pleochroism : None

Strength : N/A

Pleochroism Colors : None

Heat : Avoid heating

Acids : Attacked by acids and/ or chemicals

Light : Stable

Polish Luster : Vitreous

Fracture : Granular to uneven

Fracture Luster : Greasy to dull

Clarity Type : N/A

Tones : N/A

Saturations : N/A

Cause of Color : variable

Enhancements : Opticon, lacquer coating. This treatment can be identified by magnification of cracks and porous areas

Cleavage : Several Directions.

Color Range : Gray, brown many iridescent colors Grayish, brownish

Transparency : Opaque

Phenomena : Iridescence

Separations : Ammonite from other minerals-
It has a unique appearance and is usually not confused with any other material.

Identifying Characteristics and information
Ammonite is a fossilized, mineralized shell with mosaic pattern or iridescence.The iridescence is caused by diffraction of aragonite crystal plates.May have a spiral structure resembling a nautilus shell.

Also known as ammolite and sometimes calcentine.

Spectral Data
Not Diagnostic.

Trade Names and Misnomers
Ammolite, korite, aapaok and calcenite .

Notes:- Canade is the only source of iridescent material.

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Ammonite