The most distinctive feature of hydrothermally grown synthetic corundum is wavy growth zoning.

Synthetic Sapphire  •  Hydrothermal  •  Enhancements: None Detected (None)  •  Lighting Conditions: Dark Field
Photographer: E. Billie Hughes  •  Image Number: R-001-5993-1

Hughes, R.W., Manorotkul, W. et al. (2017) Ruby & Sapphire: A Gemologist's Guide. Bangkok, Lotus Publishing, 816 pp.; RWHL*.

The small pinpoints in this image are gas bubbles confirming the synthetic nature of this flame-fusion sapphire.

Synthetic Sapphire  •  Verneuil  •  Enhancements: None Detected (None)  •  Lighting Conditions: Dark Field
Photographer: E. Billie Hughes  •  Image Number: A-002-0288-3

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

Plato-Sandmeier polysynthetic twin lines in a synthetic flame-fusion sapphire.

Synthetic Sapphire  •  Verneuil  •  Enhancements: None Detected (None)  •  Lighting Conditions: Crossed polars + Immersion + Blue filter
Photographer: E. Billie Hughes  •  Image Number: A-002-0288-1

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

Hughes, R.W. (1997) Ruby & Sapphire. Boulder, CO, RWH Publishing, 512 pp.; RWHL*.

Hughes, R.W. (2005) Proletarian Gemology: The Blue Filter. Bangkok, Lotus Gemology; RWHL.

Eppler, W.F. (1964) Polysynthetic twinning in synthetic corundum. Gems & Gemology, Vol. 11, No. 6, Summer, pp. 169–175; RWHL*.

Immersion in di-iodomethane, accompanied with a blue filter, reveals the curved color banding in this synthetic sapphire.

Synthetic Sapphire  •  Verneuil  •  Enhancements: None Detected (None)  •  Lighting Conditions: Diffuse Light Field + Immersion + Blue Filter
Photographer: E. Billie Hughes  •  Image Number: A-001-5127-1

Hughes, R.W. (2005) Proletarian Gemology: The Blue Filter. Bangkok, Lotus Gemology; RWHL.

When a yellow sapphire is immersed in a yellow liquid like methylene iodide, it is difficult to see the growth zoning. Placement of a blue filter under the immersion cell provides the necessary contrast to easily spot features such as the curved color banding seen here, which proves this stone to be a Verneuil synthetic.

Synthetic Sapphire  •  Verneuil  •  Enhancements: None Detected (None)  •  Lighting Conditions: Diffuse Light Field + Immersion + Blue Filter
Photographer: Richard W. Hughes  •  Image Number: R-001-4926-2

Hughes, R.W. (1988) Identifying yellow sapphires—two important techniques. Journal of Gemmology, Vol. 21, No. 1, pp. 23-25, RWHL*.

Hughes, R.W. and Koivula, J. (2005) Dangerous curves: Verneuil synthetic corundum. Bangkok, Lotus Gemology; RWHL.

When a yellow sapphire is immersed in a yellow liquid like methylene iodide, it is difficult to see the growth zoning, as shown here.

Synthetic Sapphire  •  Verneuil  •  Enhancements: None Detected (None)  •  Lighting Conditions: Diffuse Light Field + Immersion
Photographer: Richard W. Hughes  •  Image Number: R-001-4926-1

Hughes, R.W. (1988) Identifying yellow sapphires—two important techniques. Journal of Gemmology, Vol. 21, No. 1, pp. 23-25, RWHL*.

Hughes, R.W. and Koivula, J. (2005) Dangerous curves: Verneuil synthetic corundum. Bangkok, Lotus Gemology; RWHL.

Curved color banding in a Verneuil-grown synthetic sapphire.

Synthetic Sapphire  •  Verneuil  •  Enhancements: None Detected (None)  •  Lighting Conditions: Diffuse Light Field + Immersion
Photographer: E. Billie Hughes  •  Image Number: A-001-4461-1

Hughes, R.W. and Koivula, J. (2005) Dangerous curves: Verneuil synthetic corundum. Bangkok, Lotus Gemology; RWHL.

This synthetic pink sapphire was fractured and then appeared to have been soaked in an iron-rich solution to created orange stains in the fissures, thus simulating padparadscha. The stains developed unusual dendritic patterns, as seen here. Chemical analysis also reveal traces of lead in the fissures.

Synthetic Sapphire  •  Verneuil  •  Enhancements: ()  •  Lighting Conditions: Dark Field + Oblique Fiber Optic
Photographer: E. Billie Hughes  •  Image Number: A-001-3404-7

Hughes, E.B., Chankhanatha, C. et al. (2016) Padparadscha or pretender: Examination of an unusual pink-orange sapphire. Australian Gemmologist, Vol. 25, No. 11–12, pp. 389–392; RWHL.

This synthetic pink sapphire was fractured and then appeared to have been soaked in an iron-rich solution to created orange stains in the fissures, thus simulating padparadscha. The stains developed unusual dendritic patterns, as seen here. This fissure also shows an unusual shiny, glossy appearance. Chemical analysis also reveal traces of lead in the fissures.

Synthetic Sapphire  •  Verneuil  •  Enhancements: ()  •  Lighting Conditions: Dark Field + Oblique Fiber Optic
Photographer: E. Billie Hughes  •  Image Number: A-001-3404-6

Hughes, E.B., Chankhanatha, C. et al. (2016) Padparadscha or pretender: Examination of an unusual pink-orange sapphire. Australian Gemmologist, Vol. 25, No. 11–12, pp. 389–392; RWHL.

This synthetic pink sapphire was fractured and then appeared to have been soaked in an iron-rich solution to created orange stains in the fissures, thus simulating padparadscha. The stains developed unusual dendritic patterns, as seen here. This fissure also shows an unusual glossy appearance. Chemical analysis also reveal traces of lead in the fissures.

Synthetic Sapphire  •  Verneuil  •  Enhancements: ()  •  Lighting Conditions: Dark Field + Oblique Fiber Optic
Photographer: E. Billie Hughes  •  Image Number: A-001-3404-5

Hughes, E.B., Chankhanatha, C. et al. (2016) Padparadscha or pretender: Examination of an unusual pink-orange sapphire. Australian Gemmologist, Vol. 25, No. 11–12, pp. 389–392; RWHL.

This synthetic pink sapphire was fractured and then appeared to have been soaked in an iron-rich solution to created orange stains in the fissures, thus simulating padparadscha. The stains developed unusual dendritic patterns, as seen here. Chemical analysis also reveal traces of lead in the fissures.

Synthetic Sapphire  •  Verneuil  •  Enhancements: ()  •  Lighting Conditions: Dark Field + Oblique Fiber Optic
Photographer: E. Billie Hughes  •  Image Number: A-001-3404-4

Hughes, E.B., Chankhanatha, C. et al. (2016) Padparadscha or pretender: Examination of an unusual pink-orange sapphire. Australian Gemmologist, Vol. 25, No. 11–12, pp. 389–392; RWHL.

This synthetic pink sapphire was fractured and then appeared to have been soaked in an iron-rich solution to created orange stains in the fissures, thus simulating padparadscha. The stains developed unusual dendritic patterns, as seen here. Chemical analysis also reveal traces of lead in the fissures. In this image we can also see fine growth needles in parallel lines.

Synthetic Sapphire  •  Verneuil  •  Enhancements: ()  •  Lighting Conditions: Dark Field + Oblique Fiber Optic
Photographer: E. Billie Hughes  •  Image Number: A-001-3404-3

Hughes, E.B., Chankhanatha, C. et al. (2016) Padparadscha or pretender: Examination of an unusual pink-orange sapphire. Australian Gemmologist, Vol. 25, No. 11–12, pp. 389–392; RWHL.