Dendritic Quartz | Gemopedia

This agate variety is termed "dendritic" due to its internal collection of dendrites. Dendrites are fern-like inclusions of iron, manganese, or other metallic oxides that create bold patterns within the gem. Typically, dendritic agates are cut into slabs to best exhibit nature's artwork. As you might guess, these pieces are one-of-a-kinds, as no two dendritic patterns are exactly the same. The internal dendrites may appear black, dark gray, brown or green and, in rare instances, even red.
Colors
Colorless, Brown, Orange, Yellow

Dendritic Quartz Classification

Common Name

Dendritic Quartz

Species

Quartz

Variety

Dendritic Quartz

Colors

Colorless, Brown, Orange, Yellow

Alternate Names

Gemstone Groups

Key Separations

Refractive index, appearance, birefringence, optic character and optic figure. A bull's-eye optic figure is determinative for quartz; may also show Airy's spiral optic figure and Brazil-law twinning under crossed polarizing filters.

Comments

Dendrites are crystals that grow in a fractal pattern and have an appearance similar to moss or branches.

Dendritic Quartz Optical Properties

Transparency

Transparent - Translucent

Refractive Index

1.544-1.553
Tolerance:very constant

Birefringence

0.009

Optic Character

Uniaxial

Optic Sign

Positive

Polariscope Reaction

Doubly Refractive (DR)

Fluorescence

SWUV:
LWUV:

CCF Reaction

Pleochroism

None

Dispersion

Strength: weak fire Value: 0.013

Comments

Dendritic Quartz Chemistry & Crystallography

Chemical Name

silicon dioxide (aka silica)

Chemical Formula

SiO2

Synthesis

Crystal System

Trigonal

Classification

Silicate

Nature

Natural

Crystallinity

Crystalline

Comments

Dendritic Quartz Characteristic Physical Properties

Hardness

7

Streak

White

Specific Gravity

2.64-2.69 Typical:2.66

Toughness

Good

Inclusions

Dendritic quartz will have dendrite inclusions and may contain liquid, two-phase and three-phase inclusions, negative crystals, minerals, needles, rutile and iron particles.

Luster

Vitreous

Stability

Good

Fracture

Conchoidal

Cleavage

None

Comments

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