Small hexagonal, transparent, doubly refractive crystals cluster in this spinel from Vietnam.

Natural Spinel  •  Vietnam  •  Enhancements: Fissure Filling with colorless Oil/resin (FF-O1); No indications of heating (No indications of heating)  •  Lighting Conditions: Diffuse Light Field (Transmitted Light)
Photographer: E. Billie Hughes  •  Image Number: A-001-8584-2

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 2. Basel, Switzerland, Opinio Publishers, 830 pp.; RWHL*.

Stellate dislocations form a star-like cushion around a crystal in this untreated spinel from Vietnam.

Natural Spinel  •  Vietnam  •  Enhancements: None Detected (None)  •  Lighting Conditions: Dark Field
Photographer: E. Billie Hughes  •  Image Number: A-001-6229-3

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 2. Basel, Switzerland, Opinio Publishers, 830 pp.; RWHL*.

A small cluster of prismatic crystals in a pink spinel from Tajikistan.

Natural Spinel  •  Tajikistan; Kuh-i-Lal  •  Enhancements: None Detected (None)  •  Lighting Conditions: Dark Field + Oblique Fiber Optic
Photographer: Patharaphum Sudprasert  •  Image Number: A-002-1674-2

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 2. Basel, Switzerland, Opinio Publishers, 830 pp.; RWHL*.Vol. 2 for spinel

This euhedral crystal in a Sri Lankan spinel displays obvious growth striations on its surface. Striations actually consist of tiny crystal faces and result from oscillatory growth, where growth oscillates between two different faces, each growing for just a brief time.

Natural Spinel  •  Sri Lanka (Ceylon)  •  Enhancements: None Detected (None)  •  Lighting Conditions: Dark Field + Diffuse Fiber Optic
Photographer: Patharaphum Sudprasert  •  Image Number: A-002-0761-1

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 2. Basel, Switzerland, Opinio Publishers, 830 pp.; RWHL*.Vol. 2 for spinel

Cluster of tiny spinel octahedra in a spinel from Sri Lanka. These are a common sight in spinels from a variety of locations.

Natural Spinel  •  Sri Lanka (Ceylon)  •  Enhancements: None Detected (None)  •  Lighting Conditions: Dark Field
Photographer: Richard W. Hughes  •  Image Number: A-002-0282-1

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 2. Basel, Switzerland, Opinio Publishers, 830 pp.; RWHL*.

This web-like fingerprint covers an untreated spinel from Vietnam.

Natural Spinel  •  Vietnam  •  Enhancements: None Detected (None)  •  Lighting Conditions: Diffuse Light Field (Transmitted Light)
Photographer: E. Billie Hughes  •  Image Number: A-001-9321-3

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 2. Basel, Switzerland, Opinio Publishers, 830 pp.; RWHL*.

Web-like fingerprint and a negative crystal with a CO2 bubble inside an untreated spinel from Vietnam.

Natural Spinel  •  Vietnam  •  Enhancements: None Detected (None)  •  Lighting Conditions: Diffuse Light Field (Transmitted Light)
Photographer: E. Billie Hughes  •  Image Number: A-001-9321-1

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 2. Basel, Switzerland, Opinio Publishers, 830 pp.; RWHL*.

Melted fingerprints showing heat altered octahedra give evidence of heat treatment in this cobalt diffused spinel.

Natural Spinel  •  No Origin  •  Enhancements: Heat + Diffusion of external coloring agents (H-D); Heat + Fissure Healing (H-FH)  •  Lighting Conditions: Diffuse Light Field (Transmitted Light)
Photographer: E. Billie Hughes  •  Image Number: A-001-9346-3

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.

Melted fingerprints showing heat altered octahedra give evidence of heat treatment in this cobalt diffused spinel.

Natural Spinel  •  No Origin  •  Enhancements: Heat + Diffusion of external coloring agents (H-D); Heat + Fissure Healing (H-FH)  •  Lighting Conditions: Diffuse Light Field (Transmitted Light)
Photographer: E. Billie Hughes  •  Image Number: A-001-9346-2

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.

A melted crystal set against a backdrop of tiny melted octahedra provide evidence of heat treatment in this cobalt diffused spinel.

Natural Spinel  •  No Origin  •  Enhancements: Heat + Diffusion of external coloring agents (H-D); Heat + Fissure Healing (H-FH)  •  Lighting Conditions: Dark Field
Photographer: E. Billie Hughes  •  Image Number: A-001-9346-1

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.

Dislocations decorate the interior of this spinel from Vietnam. These may sometimes alter to hogbomite.

Natural Spinel  •  Vietnam  •  Enhancements: None Detected (None)  •  Lighting Conditions: Dark Field + Shadowing
Photographer: E. Billie Hughes  •  Image Number: R-001-7697-4

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 2. Basel, Switzerland, Opinio Publishers, 830 pp.; RWHL*.

Chauviré, B., Rondeau, B. et al. (2015) Blue spinel from the Luc Yen district of Vietnam. Gems & Gemology, Vol. 51, No. 1, Spring, pp. 2–17; RWHL.

Dislocations decorate the interior of this spinel from Vietnam. These may sometimes alter to hogbomite.

Natural Spinel  •  Vietnam  •  Enhancements: None Detected (None)  •  Lighting Conditions: Dark Field + Shadowing
Photographer: E. Billie Hughes  •  Image Number: R-001-7697-1

Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 2. Basel, Switzerland, Opinio Publishers, 830 pp.; RWHL*.

Chauviré, B., Rondeau, B. et al. (2015) Blue spinel from the Luc Yen district of Vietnam. Gems & Gemology, Vol. 51, No. 1, Spring, pp. 2–17; RWHL.