Mineral Information and Data:

ZrO2 [CNMNC approved formula]

Named for Joseph Baddeley, who first called attention to the Sri Lankan material.

IMA status : Valid species (Pre-IMA 1892) Grandfathered
(8th edition) :  
  (04) Simple Oxides
  (04.04) with a cation charge of 4+ (A++++ O2)
(10th edition) :
  (04) Oxides and Hydroxides
  (04.D) Metal:Oxygen = 1:2 and similar
  (04.DE) With medium-sized cations; with various polyhedra
Crystal system: Monoclinic System
Point group (H-M): 2/m — prismatic
Unit cell: a = 5.1505Å, b = 5.2116Å, c = 5.3173Å; β = 99.23°
Crystal Habit: Crystals commonly tabular on {100} and somewhat elongated on [010], or short to long prismatic along [001], to 6 cm; rarely equant; prism faces striated parallel to [001]; also botryoidal masses with radially fibrous structure and concentric banding.
Twinning: Ubiquitous; on {100} and {110}, both may be polysynthetic; rare on {201}
Color: Colorless to yellow, green, greenish or reddish brown, brown, iron-black; colorless to brown in transmitted light.
Diaphaneity: Transparent; in dark-colored specimens, only in thin fragments.
Luster: Greasy to vitreous; nearly submetallic in black crystals.
Hardness (Mohs): 6.5
Measured Density: 5.40 – 6.02 g/cm3
Cleavage: {001} nearly perfect, {010} and {110} less perfect
Tenacity: Brittle
Fracture: Subconchoidal to uneven
Streak: White to brownish white
Geologic Setting: An accessory mineral in carbonatites and kimberlites; in syenites, diabases, gabbros, anorthosites; detrital in gem gravels. In lunar basalt, tektites, and meteorites.
Mineral Association: Ilmenite, zirkelite, apatite, magnetite, perovskite (Jacupiranga mine, Brazil); fluorite, nepheline, pyrochlore, allanite (Monte Somma, Italy)
Luminescent Properties: Blue-green cathodoluminescence.
Other Properties: Gemstone Extremely Rare.


Origin: Sao Paulo, Brazil.
Sample size: 11 x 9 x 3 cm
Photo: Tom Loomis


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