Crystal Green Rutile

Chemical Formula

TiO₂

Composition

Titanium dioxide, often with iron, occasionally with some minor niobium or tantalum.
 

Variable Formula

(Ti,Fe)O₂

Color

Dark-red, metallic-gray, brownish-red, orange-red, reddish-black, golden-yellow, straw yellow

Streak

White to light brown

Hardness

6 - 6.5

Crystal System

Tetragonal

3D Crystal Atlas
 

Crystal Forms 
and Aggregates

As long and slender, straight prismatic crystals, often deeply striated and with steep complex terminations. Also in short prismatic and thick stubby crystals. Twinning is very common, with various forms including sixlings, eightlings (both in the form of endemic rutile twins), knee-shaped twins, and v-shaped twins.

Often in capillary needles and dense reticulated forms, in acicular habit, in delicate snowflake-like aggregates, and in star-shaped formations of dense needle groupings. Thin acicular crystals and needles are commonly frozen within other minerals, especially Quartz. May also be grainy, massive, in veins, and in roundedwaterworn pebbles.

Transparency

Translucent to opaque. Often transparent on thin edges and in backlighting.

Specific Gravity

4.2 - 4.3

Luster

Adamantine, submetallic

Cleavage

2,2;3,1

Fracture

Uneven

Tenacity

Brittle

In Group

Oxides; Simple Oxides

Striking Features

Color, crystal habits, luster, and high specific gravity.

Environment

Rutile comes in several different environments, including plutonic and intrusive igneous rocks and granites, metamorphic gneiss and schists, carbonatites, regional metamorphic schists, and hydrothermal replacement deposits (including veins in alpine cavities). Also in detrital river and beach deposits.
 

Rock Type

Igneous, Metamorphic

Popularity (1-4)

2

Prevalence (1-3)

2

Demand (1-3)

1