Srilankite
Current inventory: 0 gems
 

  
Srilankite was named in 1983 by Alexander Willgallis, Eveline Siegmann, and Theja Hettiaratchi after its discovery locality at Rakwana, Sabaragamuwa Province, Sri Lanka.

Discovered in 1982; IMA status: Valid (IMA Approved 1983)

Chemistry

Chemical Formula:

(Ti,Zr)O₂

Titanium Zirconium Oxide

Molecular Weight:

90.71 gm

Composition:

Zirconium

25.14 %

Zr

33.96 %

ZrO₂

Titanium

39.59 %

Ti

66.04 %

TiO₂

Oxygen

35.27 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Oxides

Strunz 8th Ed. ID:

4/D.15-20

Nickel-Strunz 10th Ed. ID:

4.DB.25

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
B : With medium-sized cations; chains of edge-sharing octahedra

Related to:

Samarskite Group. Brookite - Kuranakhite Series

Members of Group:

Samarskite Group: Calciosamarskite, Ishikawaite, Samarskite-(Y), Samarskite-(Yb), Srilankite 

Varieties:

None

Synonyms:

ICSD 69619, IMA1982-056, PDF 46-1265

Crystal Data

Crystallography:

Orthorhombic - Dipyramidal

Crystal Habit:

Tabular crystals, often twinned. As idiomorphic inclusions, less than 1 mm, intergrown with associated minerals. 

Twinning:

Interpenetration and contact twins.

Physical Properties

Cleavage:

Poor/indistinct in one direction

Fracture:

Conchoidal

Tenacity:

Brittle

Moh's Hardness:

~6.5; Vickers: VHN₁₀₀=900-1000 kg/mm²

Density:

~4.60 (g/cm³)

Luminescence:

None

Radioactivity:

Generally not radioactive but may be anomalously radioactive.

Optical Properties

Color:

Black, brownish black; dark blue in transmitted light; gray-white in reflected light.

Transparency:

Opaque, translucent in thin fragments.

Luster:

Sub-metallic to adamantine

Refractive Index:

2.380  Biaxial ( - )

Birefringence:

0.000 (Isotropic)

Dispersion:

n/a

Pleochroism:

None

Anisotropism:

Observed; internal reflections: brown, dark blue

Occurances

Geological Setting:

In pebbles found in concentrates from a placer gemstone mine.

Common Associations:

Zirconolite, Baddeleyite, Geikielite, Spinel, Perovskite

Common Impurities:

n/a

Type Locality:

Rakwana, Sabaragamuwa Province, Sri Lanka

Year Discovered:

1982; IMA approved 1983

View mineral photos:

n/a

More Information

Mindat.org
Webmineral.com

Srilankite is a very rare titanium zirconium oxide mineral. It is a member of the Samarskite Group of minerals that also includes Samarskite-(Y). Srilankite is usually found as minute inclusions (less than 1 mm) in other associated minerals. Independent crystals do exist but are extremely rare so gems are even rarer. Crystals are typically opaque, black to dark brownish black with sub-metallic to adamantine luster.

Srilankite was named in 1983 by Alexander Willgallis, Eveline Siegmann, and Theja Hettiaratchi after its discovery locality at Rakwana, Sabaragamuwa Province, Sri Lanka. This is also the only locality in the world where Srilankite has been found.
 

  
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