Jasper | Gemopedia

Jasper is an opaque, fine grained variety of chalcedony quartz. It is typically found in red, yellow, brown or green colors and is generally spotted with these colors. Its name comes from the Latin word for the gem, iaspis, meaning "spotted stone."
Alternate
Names
Agate Jasper, Banded Jasper, Basanite, Egyptian Jasper, Hornstone, Nunkirchner Jasper, Scenic Jasper, Silex
Colors
Almost Any Color Except Black

Jasper Classification

Common Name

Jasper

Species

Quartz

Variety

Chalcedony

Colors

Almost Any Color Except Black

Alternate Names

Agate Jasper, Banded Jasper, Basanite, Egyptian Jasper, Hornstone, Nunkirchner Jasper, Scenic Jasper, Silex

Gemstone Groups

Key Separations

RI, SG, appearance and fracture; color filter reaction if dyed.

Comments

Can be any color or variety of colors except black or colors covered by other varieties. The opaque version of chalcedony. Misnomer: dyed blue jasper Swiss lapis or German lapisJasper is the opaque cryptocrystalline form of quartz (chalcedony) and are basically silica cement. Egyptian jasper: strongly yellow and red.Hornstone or chert: fine grained gray, brown-red and rarely green or black.Scenic jasper: iron oxide staining makes designs that give the appearance of landscapes.Silex: Yellow and brown-red spotted or striped. Brecciated Jasper: show cracks because they were broken by tectonic movement and then cemented back together.Orbicular Jasper: (Ocean or Poppy) show sphere or flower-like patters. Scenic Jasper: have a landscape like appearance.

Jasper Optical Properties

Transparency

Opaque

Refractive Index

1.535-1.539

Birefringence

0.004-0.004

Optic Character

Uniaxial

Optic Sign

Positive

Polariscope Reaction

Aggregate (AGG)

Fluorescence

SWUV: Inert
LWUV: Inert

CCF Reaction

Dyed blue: pinkish

Pleochroism

None

Dispersion

Strength: none

Comments

Jasper Chemistry & Crystallography

Chemical Name

silicon dioxide (aka silica)

Chemical Formula

SiO2

Synthesis

Crystal System

Trigonal

Classification

Silicate

Nature

Natural

Crystallinity

Polycrystalline

Comments

Jasper Characteristic Physical Properties

Hardness

6.5-7

Streak

White, Yellow, Brown And Red

Specific Gravity

2.5-2.6 Typical:2.6

Toughness

Excellent

Inclusions

Jasper is sometimes dyed often to look like lapis but will not have calcite or pyrite inclusions with higher luster. The stone will have a finely grained structure.

Luster

Vitreous

Stability

Good

Fracture

Conchoidal, Granular

Cleavage

None

Comments

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