Texture clouds form sharp, angular zones in this Cambodian sapphire.
Natural Sapphire • Cambodia; Pailin • Enhancements: None Detected (None) • Lighting Conditions: Dark Field + Oblique Fiber OpticPhotographer: E. Billie Hughes • Image Number: A-001-3390-4 • Date Posted: 25 November 2015
Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 3. Basel, Switzerland, Opinio Publishers, 672 pp.; RWHL*.
Tiny red uranium pyrochlore crystals glow in this sapphire from Pailin, Cambodia. These crystals are a diagnostic inclusion for magmatic sapphires.
Natural Sapphire • Cambodia; Pailin • Enhancements: None Detected (None) • Lighting Conditions: Dark Field + Oblique Fiber OpticPhotographer: E. Billie Hughes • Image Number: A-001-3390-3 • Date Posted: 25 November 2015
This transparent crystal was an obstacle to this sapphire’s growth, creating a “comet trail” stream of fine particles behind it. This example is in a Pailin sapphire.
Natural Sapphire • Cambodia; Pailin • Enhancements: None Detected (None) • Lighting Conditions: Dark Field + Oblique Fiber OpticPhotographer: E. Billie Hughes • Image Number: A-001-3390-2 • Date Posted: 25 November 2015
A tiny red uranium pyrochlore octahedron glows in this sapphire from Pailin, Cambodia. These pyrochlore crystals are a diagnostic inclusion for magmatic sapphires.
Natural Sapphire • Cambodia; Pailin • Enhancements: None Detected (None) • Lighting Conditions: Dark Field + Oblique Fiber OpticPhotographer: E. Billie Hughes • Image Number: A-001-3390-1 • Date Posted: 25 November 2015
These droplet-like surface markings may superficially look like water or oil, but they cannot be wiped or scraped off. They are actually spall marks, a result of heat treatment that affects the surface of the stone. Often a heated stone will be repolished to remove such markings.
Natural Sapphire • Sri Lanka (Ceylon) • Enhancements: Heat (H) • Lighting Conditions: Fiber Optic: Diffuse OverheadPhotographer: E. Billie Hughes • Image Number: A-001-3260-2 • Date Posted: 16 November 2015
Hughes, R.W., Manorotkul, W. et al. (2017) Ruby & Sapphire: A Gemologist's Guide. Bangkok, Lotus Publishing, 816 pp.; RWHL*.
Short needles and exsolved particles in a spinel from Mahenge, Tanzania. Clouds of dust-like particles are typical for Mahenge spinel.
Natural Spinel • Tanzania; Mahenge • Enhancements: None Detected (None) • Lighting Conditions: Dark FieldPhotographer: E. Billie Hughes • Image Number: A-001-3366-1 • Date Posted: 24 November 2015
Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 2. Basel, Switzerland, Opinio Publishers, 830 pp.; RWHL*.
Saeseaw, S., Wang, W. et al. (2009) Distinguishing Heated Spinels from Unheated Natural Spinels and from Synthetic Spinels. Gemological Institute of America, 13 pp.; RWHL.
These octahedral crystals, a characteristic feature of spinel, are surrounded by accretion clouds.
Natural Spinel • Myanmar (Burma); Mogok/Namya • Enhancements: None Detected (None) • Lighting Conditions: Dark FieldPhotographer: E. Billie Hughes • Image Number: A-001-3254-1 • Date Posted: 16 November 2015
Many crystals contain shallow fissures on their surfaces. In sapphires from Sri Lanka, Myanmar and Madagascar, these fissures often contain yellow stains. High-temperature heating not only destroys the yellow stains, but begins a process of healing, where the fissures turn white and start forming fingerprints.
Natural Sapphire • Madagascar • Enhancements: None Detected (None) • Lighting Conditions: Diffuse Light Field (Transmitted Light)Photographer: Richard W. Hughes • Image Number: A-001-3319-2 • Date Posted: 19 November 2015
Koivua, J.I. (2013) Useful visual clue indicating corundum heat treatment. Gems & Gemology, Vol. 49, No. 3, Fall, pp. 160–161; RWHL*.
Dense clouds of exsolved titanium-bearing minerals have created the fanciful scenery within this untreated sapphire from Madagascar. As the crystal cooled these growing clouds sucked titanium from the surrounding sapphire, thus robbing it of an essential chromophore. The result is decolorized zones surrounding the clouds, a process dubbed “chromophore cannibalization” by microphotographic maestro John Koivula.
Natural Sapphire • Madagascar • Enhancements: None Detected (None) • Lighting Conditions: Fiber Optic: Oblique + ShadowingPhotographer: Richard W. Hughes • Image Number: A-001-3319-1 • Date Posted: 19 November 2015
Orange primary rutile crystals stand out against a backdrop of exsolved particles in a hexagonal pattern in this Montana sapphire.
Natural Sapphire • USA (Montana); Non-Yogo • Enhancements: None Detected (None) • Lighting Conditions: Fiber Optic: ObliquePhotographer: E. Billie Hughes • Image Number: R-001-3238-1 • Date Posted: 15 November 2015
Hughes, R.W. (1997) Ruby & Sapphire. Boulder, CO, RWH Publishing, 512 pp.; RWHL*.
With magnification, curved straie can be seen in this piece of Verneuil flame-fusion synthetic sapphire that was masquerading as a piece of natural rough.
Synthetic Sapphire • Verneuil • Enhancements: None Detected (None) • Lighting Conditions: Fiber Optic: ObliquePhotographer: E. Billie Hughes • Image Number: A-001-2108-4 • Date Posted: 25 August 2015
Hughes, R.W. and Koivula, J. (2005) Dangerous curves: Verneuil synthetic corundum. Bangkok, Lotus Gemology; RWHL.
This piece of Verneuil flame fusion synthetic sapphire was treated to make it look like a natural stone. However, the charade is over when the stone is viewed under shortwave ultraviolet light: it displays a chalky fluorescence that is seen in many Verneuil synthetics. (Note that natural stones may also display a chalky fluorescence, but it is usually in a zoned pattern.)
Synthetic Sapphire • Verneuil • Enhancements: None Detected (None) • Lighting Conditions: Ultraviolet: ShortwavePhotographer: E. Billie Hughes • Image Number: A-001-2108-3 • Date Posted: 25 August 2015