Examination of Three-Phase Inclusions in Colorless, Yellow, and Blue Sapphires from Sri Lanka

Schmetzer, Karl; Medenbach, Olaf

doi:10.5741/gems.24.2.107

Cited by 8 publications

(5 citation statements)

References 21 publications

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“…The inclusions in untreated Sri Lankan padparadschas in this study are broadly similar to those in most Sri Lankan sapphires ( Figures A10 -A12). These include zircon crystals, occasionally with tension cracks, negative crystals, tiny rutile needles, other unidentified mineral inclusions, and cavities filled with fluid and multiphase inclusions (see Koivula, 1986), some with diaspore needles (see Schmetzer and Medenbach, 1988). Multiphase inclusions may also contain graphite and rutile, gaseous and liquid CO 2 and diaspore needles (Notari, 1996; see also De Maesschalck and Oen, 1989;Francis et al, 2003).…”

Section: Sri Lanka Untreatedmentioning

confidence: 99%

A venture into the interior of natural diamond: genetic information and implications for the gem industry

Bulanova¹,

Varshavsky²,

Kotegov³

2005

Journ of Gemm

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Natural diamonds are rarely homogeneous. Crystals contain evidence of complicated histories of growth, changes of habit, chemistry, stages of growth and resorption. To extract genetic information recorded during diamond formation they should be studied by modern methods of microanalysis in polished plates. The best way to polish diamond to reveal internal zonation is described and the interpretation of different types of internal morphology of diamonds from cathodoluminescence imagery is given. Knowledge of the internal structures of diamonds is not only useful for scientific observations, but also allows a better determination of their likely behaviour during the cutting and polishing processes. This gives an opportunity for more economic use of individual stones during gem production.

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Section: Sri Lanka Untreatedmentioning

confidence: 99%

A venture into the interior of natural diamond: genetic information and implications for the gem industry

Bulanova¹,

Varshavsky²,

Kotegov³

2005

Journ of Gemm

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“…As a matter of fact, the variety of inclusions observed in sapphires is a function of the geological origin and, in some cases, typical of specific deposits. For instance, tourmaline prisms crystals and a needle-like rutile (TiO 2 ) inclusions are common in sapphire from Kashmir 14 ; diaspore (AlO(OH)) as solid phase in threefold-phase inclusions is typical in unheated Sri Lanka sapphire 15 ; fluid inclusions, where the fluid consists of impure CO 2 (probably mixed with H 2 S), are related to magmatic origin from marble deposits (e.g. Pakistan and Afghanistan).…”

Section: Introductionmentioning

confidence: 99%

Micro‐Raman spectroscopy applied to the study of inclusions within sapphire

Palanza¹,

Martino²,

Палеари³

et al. 2008

J Raman Spectroscopy

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The present research concerns the characterization of samples of corundum (Al 2 O 3 ), varieties of sapphire, by micro-Raman spectroscopy. Ten samples of natural corundum from Australia, Madagascar, Sri Lanka, Thailand, Tanzania, and Vietnam were studied. After standard gemmological analysis, micro-Raman analysis was also performed in order to identify mineral inclusions within the sapphire samples and to obtain information on the geological genres of the minerals. Several inclusions were evidenced within the sapphires and identified by Raman spectroscopy thanks to a confocal spectrometer, which allowed detection also below the external surface of the gem. Finally, the Raman spectra are discussed taking into account the provenance of the samples and their optical absorption.

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“…In cavities at the surface, some Fe-hydrox- Gem-quality rubies and other corundum varieties often contain microscopic inclusions, among them specifically diaspore and goethite. Diaspore is commonly found in corundum as a retrograde hydrothermal alteration product, e.g., as whitish acicular needles in ruby fissures or as tiny prismatic solids in fluid inclusions and negative inclusions [50]. Goethite is often present in corundum in fissures and (tiny) hollow channels as a pedogenic weathering product [43], introduced by Fe-enriched meteoric waters circulating within the gravels of secondary gem deposits.…”

Section: Discussionmentioning

confidence: 99%

Dehydration of Diaspore and Goethite during Low-Temperature Heating as Criterion to Separate Unheated from Heated Rubies and Sapphires

Krzemnicki,

Lefèvre,

Zhou

et al. 2023

Minerals

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Gem-quality rubies and sapphires are often commercially heat treated at about 800 °C or higher to enhance their color and clarity, and hence quality. For this study, selected corundum samples containing diaspore and goethite inclusions were heated step-by-step to a maximum of 1000 °C with the aim of monitoring the dehydration and phase transformation of these oxyhydroxides to corundum and hematite during heating. Based on our experiments and in agreement with the literature, the dehydration of diaspore in corundum occurs between 525 and 550 °C, whereas goethite transforms to hematite between 300 and 325 °C. As both diaspore and goethite may be present as inclusions in rubies, sapphires, and other corundum varieties (e.g., pink sapphires, padparadscha), these dehydration reactions and phase transformations can be considered important criteria to separate unheated from heated stones, specifically in cases in which other methods (e.g., microscopy, FTIR) are unsuccessful.

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Examination of Three-Phase Inclusions in Colorless, Yellow, and Blue Sapphires from Sri Lanka

Cited by 8 publications

References 21 publications

A venture into the interior of natural diamond: genetic information and implications for the gem industry

A venture into the interior of natural diamond: genetic information and implications for the gem industry

Micro‐Raman spectroscopy applied to the study of inclusions within sapphire

Dehydration of Diaspore and Goethite during Low-Temperature Heating as Criterion to Separate Unheated from Heated Rubies and Sapphires

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