Quahog Pearls | Gemopedia

Among America's rarest and most stunning pearls, quahog pearls were first valued by Native Americans along the coast of New England. This non-nacreous calcareous concretion forms in colors from white to brown, to purple and lilac in round, button and teardrop shapes. Such pearls are typically collected by fishermen as a result of harvesting the meat of the shellfish.
Alternate
Names
Cohog And Quohog
Colors
White, Beige, Brown, Black, Purple, Lavender

Quahog Pearls Classification

Common Name

Quahog Pearls

Species

NA

Variety

Colors

White, Beige, Brown, Black, Purple, Lavender

Alternate Names

Cohog And Quohog

Gemstone Groups

Key Separations

Appearance, RI, birefringence blink and magnification. A "tooth test" is commonly used in which a pearl is rubbed against a tooth; if gritty, this is an indication that the surface is nacre, versus plastic and glass imitations that feel smooth.

Comments

Quahog pearls were used as trade goods by Native Americans. They are produced by the bivalve clam Venus mercenaria or Mercenaria mercenaria. Most prized specimens are the lavender and purple shades.

Quahog Pearls Optical Properties

Transparency

Translucent - Opaque

Refractive Index

1.53-1.685

Birefringence

0.155

Optic Character

NA

Optic Sign

NA

Polariscope Reaction

Aggregate (AGG)

Fluorescence

SWUV:
LWUV:

CCF Reaction

Pleochroism

None

Dispersion

Comments

Quahog Pearls Chemistry & Crystallography

Chemical Name

Calcium carbonate, conchiolin and water

Chemical Formula

CaCO3 with H2O and other organic materials

Synthesis

Crystal System

NA

Classification

Organic

Nature

Natural

Crystallinity

Aggregate

Comments

Quahog Pearls Characteristic Physical Properties

Hardness

2.5-4.5

Streak

Specific Gravity

2.61-2.85

Toughness

Good

Inclusions

Quahog pearls are non-nacreous with fibrous structure. They have a color banding that sometimes creates an "eye" effect.

Luster

Dull

Stability

Poor

Fracture

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