Tiny birefringent crystals in a Madagascar sapphire. Many of this have growth tubes connected to them, giving the appearance of balloons on a string.

Natural Sapphire  •  Madagascar  •  Enhancements: None Detected (None)  •  Lighting Conditions: Fiber Optic: Oblique
Photographer: Richard W. Hughes  •  Image Number: A-001-3204-1

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 3. Basel, Switzerland, Opinio Publishers, 672 pp.; RWHL*.

Three indented dots are visible on the girdle of a sapphire. These microscopic dots indicate that the stone has undergone testing with LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry), a type of spectrometry that allows for chemical analysis of the stone.

Natural Sapphire  •  Madagascar  •  Enhancements: None Detected (None)  •  Lighting Conditions: Fiber Optic: Oblique
Photographer: E. Billie Hughes  •  Image Number: A-001-3153-1

Abduriyim, A. and Kitawaki, H. (2006) Applications of Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) to gemology. Gems & Gemology, Vol. 42, No. 2, Summer, pp. 98–118; RWHL*.

A small cluster of transparent zircon crystals with no signs of heat alteration are a welcome sight in this unheated Madagascar sapphire. Should the gem have been heat treated at temperatures typical for blue sapphire, these zircon crystals would have become cloudy and whitish and the small tension fractures around them would have begun to heal.

Natural Sapphire  •  Madagascar  •  Enhancements: None Detected (None)  •  Lighting Conditions: Dark Field + Oblique Fiber Optic
Photographer: E. Billie Hughes  •  Image Number: A-001-3163-1

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 3. Basel, Switzerland, Opinio Publishers, 672 pp.; RWHL*.

A winged monazite crystal hovers above a backdrop of rounded zircon crystals in this pink sapphire from southern Madagascar.

Natural Sapphire  •  Madagascar  •  Enhancements: None Detected (None)  •  Lighting Conditions: Fiber Optic: Oblique
Photographer: Richard W. Hughes  •  Image Number: A-001-2574-1

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 3. Basel, Switzerland, Opinio Publishers, 672 pp.; RWHL*.

Angular growth zoning with fine texture clouds in transmitted light in a sapphire from Madagascar.

Natural Sapphire  •  Madagascar  •  Enhancements: None Detected (None)  •  Lighting Conditions: Fiber Optic: Transmitted
Photographer: Richard W. Hughes  •  Image Number: A-001-2578-2

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 3. Basel, Switzerland, Opinio Publishers, 672 pp.; RWHL*.

Angular growth zoning with fine texture clouds as seen with oblique fiber-optic illumination in a sapphire from Madagascar.

Natural Sapphire  •  Madagascar  •  Enhancements: None Detected (None)  •  Lighting Conditions: Fiber Optic: Oblique
Photographer: Richard W. Hughes  •  Image Number: A-001-2578-1

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 3. Basel, Switzerland, Opinio Publishers, 672 pp.; RWHL*.

While chalky shortwave fluorescence is generally a strong indication of heat treatment, in rare cases untreated Madagascar sapphires can display superficial chalky patches associated with colorless zones in the stone, as shown here.

Natural Sapphire  •  Madagascar  •  Enhancements: None Detected (None)  •  Lighting Conditions: Ultraviolet: Shortwave
Photographer: Richard W. Hughes  •  Image Number: A-001-1183-1

Hughes, R.W. and Emmett, J.L. (2005) Heat Seeker: UV fluorescence as a gemological tool. The Guide, Vol. 24, No. 5, Part 1, Sept.–Oct., pp. 1, 4–7; RWHL*.

A small crystal with streams of particles coming off it in a heated Madagascar sapphire. Particle streams such as this form because an inclusion creates a barrier to growth behind it, resulting in the trapping of tiny fluid inclusions.

Natural Sapphire  •  Madagascar  •  Enhancements: Heat (H)  •  Lighting Conditions: Fiber Optic: Oblique
Photographer: Richard W. Hughes  •  Image Number: A-001-0983-1

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 3. Basel, Switzerland, Opinio Publishers, 672 pp.; RWHL*.

Irregular crystals are seen against a backdrop of sharp angular growth zoning in this untreated sapphire from Madagascar.

Natural Sapphire  •  Madagascar  •  Enhancements: None Detected (None)  •  Lighting Conditions: Fiber Optic: Transmitted
Photographer: Richard W. Hughes  •  Image Number: A-001-0969-1

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 3. Basel, Switzerland, Opinio Publishers, 672 pp.; RWHL*.

A blocky zircon crystal in a pink sapphire from Madagascar’s Ilakaka region.

Natural Sapphire  •  Madagascar  •  Enhancements: None Detected (None)  •  Lighting Conditions: Fiber Optic: Oblique
Photographer: Richard W. Hughes  •  Image Number: A-001-1705-1

Wang, W., Scarratt, K. et al. (2006) The effects of heat treatment on zircon inclusions in Madagascar sapphires. Gems & Gemology, Vol. 42, No. 2, Summer, pp. 134–150; RWHL*.