RATNAPURALITE (Ti,K)Al2BsiO5 - A new gem mineral

Named in 2004 for the locality by Gubelin et al.
for D.P. Gunasekara, who first found
the gem-mineral in Sri Lanka.
ORTH. Borosilicate. Analysis (wt%):
SiO₂, 33.92; Al₂O₃, 61.15; K₂O, 0.92; TiO₂,
4.01. Boron not deteced.

The structure is closely related to dumortierite
but with extensive substitution of Si by Ti,
and K in Ratnapuralite. Dark Reddish Brown.
Chatoyancy. H = 7½. SG: 3.46. RI: ά = 1.700, β = 1.720, γ = 1.730,
Birefringence = 0.030 Biaxial (-).
Pleochroism = strong. Light cinnmon brown/reddish
clove brown/violetish brown. Steak = purple white.
Cleavage = perfect to one direction.
Uneven fracture. Microscope features:
parallel rutile needles, tiny black crystals,
and liquid feathers. Stone sizes:

Found two rough gems, one 41.50 ct and 11.07 ct.
Cut a Ratnapuralite – Cats Eye 12.69 ct,
roundish shape, measurements : 14.83x14.59x7.04mm.
Locality : Ratnapura, Sri Lanka. Discoverer :
D.P. Gunasekara. Formula from Canadian Museum of Nature.
Name confirmed by Prof. Dr. Edward J. Gubelin,
Switzerland pers.comm. with DPG., 13 October 2004.

Serendibite (gem-quality) (Ca,Na)₂(Al,Mg,Fe²⁺Fe³⁺)₆(Si,B,Al)₆O₂₀

A new gem variety, Schmetzer et al. 2002.

Named in 1903 by prior and Coomaraswamy,
for the locality, Serendib,
an old Arabic name for Ceylon. Aenigmatite-rhonite group.
TRIC. Bluish Green. H = 6½. SG: 3.44.
RI: ά = 1.697, β = 1.700, γ = 1.702, Biaxial (-).
Birefringence = 0.005. Plechroism: Strong.
Light Yellowish Green/Bluish Green/Violetish Blue.
Clarity: Transparent. Absorption Spectrum: one weak line at 470nm.

UV: Inert. Microscopic features: Polysynthetic twinning
tiny mineral inclusions and white finger print inclusions.
Locality: Ginigalgoda, Kolonne, Sri Lanka. Size:
Two faceted serendibite. These are the first faceted
serendibites recorded in the gemological literature.
One sample 0.35 ct. Emerald cut, 4.42x3.80x2.80 mm.

Second sample 0.55 ct. Triangular, mix cut 4.98x4.95x2.72 mm.
Discoverer: D.P. Gunasekara. Reference: G & G Vol.38,
No.1 pp. 73-79. Serendibite from Sri Lanka, Karl Schemetzer,
G. Bosshart, H.J. Bernhardt, E.J. Gubelin & C.P. Smith.

Mineral Serendibite : Dark Blue, Sky Blue. RI : 1.700, 1.703, 1.706 DR.
: 0.004-0.006 B (+). SG : 3.42-3.51. No Spectrum.
Locality : Gangapitiya, Ambakotte, Kandy, Sri Lanka.
Dana’s New Mneralogy, 8^th ed. 1997,
p. 1389. Dunil Palitha Gunasekara, Dip.Gem.,

Dunilite-Olivine a new member of the Olivine group, Burford et al 2000.

(Mg,Fe,Mn)₂SiO₄ Emprical Formula : (Mg _1.53 Fe _0.48 Mn _0.01)_2.02 Si _0.99 O₄
Formula contents on a basis of 4 anions.

Named in 2000 by Burford et al., for finder’s first name
Dunil P. Gunasekara, (1947b.) Gemmologist.
Olivine group. CaO : 0.09, MgO : 38.87, MnO : 0.31, FeO : 21.69,
SiO₂ : 37.61 wt%. Total : 98.57. ORTH. Habit :
crystals are tabular, flattened, rectangle shape corners
often modified by a six-sided rhomb shape crystal faces.
Colors crystals : Dark Grey-Green. Faceted Gems :
Greenish Yellow. Vitreous luster. H  = 6½. SG = 3.48. RI :
ά = 1.677, β = 1.700 and γ = 1.718, B(-).
Birefringence = 0.041. Transparent. Pleochroism :
Strong : Brownish Yellow/ Greenish Yellow.

Microscopic features : Hercynite crystals,
liquid feathers, healed fractures negative crystals,
decrepitation haloes. Absorption spectrum: 3 bands
between 500 and 450nm. (as in peridot) Occurrence:
In a huge pale greenish yellow calcite vein associated
with hercynite, magnetite, iron oxides,
ferroedenite hornblende crystals. Locality :
Katukubura Mountain, Kolonne, Sri Lanka. Reference
: Burford M. Gunasekara, D.P., (2000)
an unusual Olivine group Gemstone from Kolonne Area, Sri Lanka.
Trade Name; Dunilite. Canadian Gemmologist,
Vol.21, No.3, PP. 84-90. Muller, H.D.,
(2005) Dunilite-Olinive, MINERALIENm Welt 1/2005 Jan-Feb.

Bromellite BeO New Gem Material. McClure et al. 2002

Named in 1825 after Magnus von Bromell (1679-1731),
Swedish physician and mineralogist.
Hex. Colorless, Vitreous luster, H = 9, Cleavage (1010) perfect; (0001) good.
RI : w = 1.718, e = 1.732.
Birefringence = 0.014. U (-). UV fluorescence :
SW: weak yellow glow, LW: Inert. SG = 3.01 – 3.03. Inclusion:
Planes of liquid inclusions, transparent colorless irregular crystals,
transparent yellow rounded crystals, numerous thin needles.
The three transparent colorless stones

(0.68, 1.92, and 2.80 ct) are believed
to be the first reported faceted specimens of the mineral bromellite.
Locality: Gillemela, Ratnapura, Sri Lanka.
Found Rough 17.50 ct colorless hexagonal crystal.
Laudable supplier: Sunil Palitha Gunasekara. Reference
: McClure, S.F., (2002) Gem Trade Lab Notes : Bromellite.
Gems & Gemology, Vol. 38, No. 3, PP.250-252.
Dana’s New Mineralogy 8^th Ed, (1997), Bromellite, pp. 211

Metamict Allanite a member of the Epidote group

(Ca,Mn,Y,REE,Th)₂(Fe²⁺,Mg,Ti)(Al,Fe³⁺)₂O.Oh(Si₂O₇)(SiO₄)

Named in 2001 Grice et al. Amorphous,
CaO:11.73, MgO:0.48, MnO:0.48, Al₂O₃:15.64, FeO:10.41,
Fe₂O₃:1.85, Y₂O₃:1.59, La₂O₃:2.03,
Ce₂O₃:5.28, Pr₂O₃:0.69,
Nd₂O₃:3.44, Sm₂O₃:1.40, Gd₂O₃:0.98, Dy₂O₃:0.76,
TiO₂:0.59, ThO₂:5.36, SiO₂:31.07, H₂O:1.52 wt%.
Total: 95.52. Habit: Irregular rocks, outer surface brown. Inside dark brownish black.
Opaque. H = 6½. SG = 3.40. No Cleavage.

Fracture: uneven. Streak: gray white. RI = 1.680.
Occurrence : Associated with cassiterite,
almandine garnet and rock crystals. Year 1999. Locality
: Goluwahela, Illukpellessa, Badulla District, Sri Lanka.
Finder: D.P. Gunasekara. Named in 1810 by Thomas
Thomson for Thomas Allan (1777-1833), Scottish mineralogist,
who first observed the mineral.
Reference : Dana’s New
Mineralogy, 8^th ed. Pp. 1196. Wight.W., 2001 June 29^th,
Canadian Museum of Nature, personal comm.. DPG

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