𝗥𝗼𝘀𝗲 𝗖𝗵𝗮𝗻𝗻𝗲𝗹𝘀 𝗶𝗻 𝗦𝘆𝗻𝘁𝗵𝗲𝘁𝗶𝗰 𝗦𝗮𝗽𝗽𝗵𝗶𝗿𝗲

 

Introduction:

A light purplish-blue sapphire weighing 15.84 carats was submitted to the Laboratoire Français de Gemmologie (LFG) for testing. This stone turned out to be a synthetic sapphire, but what made it especially interesting was the presence of Rose channels — a feature usually seen in natural sapphires.

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What Are Rose Channels?

Rose channels are tiny hollow tubes inside the sapphire that always appear at the points where twin layers (called "twin lamellae") meet. These channels are positioned along the edges of certain crystal faces and form angles of about 90 degrees. Normally, these are features of natural sapphires.

Why Is This Discovery Important?

These channels and twin lines are common in natural sapphires, but very rare in synthetic ones. However, this sample — a Verneuil flame-fusion synthetic sapphire — had both features clearly visible. It challenges the assumption that Rose channels prove a gem is natural.

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Other Findings from Testing:

• Under the microscope: Clouds of bubbles and twinning planes were observed, typical of synthetic gems.

• Under UV light:

  • No reaction under long-wave UV.

  • Strong blue glow under short-wave UV.

• X-ray fluorescence testing showed no gallium, supporting that it’s synthetic.

• DiamondView imaging revealed curved growth lines, a feature of Verneuil synthetic sapphires.

• FTIR (Infrared) spectroscopy showed no absorption in the 1500–4000 cm⁻¹ range, where Rose channels in natural stones usually show signals.

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Conclusion:

Even though Rose channels and twin planes are normally signs of a natural sapphire, this case proves they can also appear in synthetic sapphires. Therefore, these features alone cannot be used to confirm whether a stone is natural.

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References / Source Credit:

This article is adapted and simplified from:

Hennebois, U., Delaunay, A., Herreweghe, A., Karampelas, S., & Fritsch, E. (2022). Synthetic sapphire with Rose channels. Gems & Gemology, 58(3), p. 387.
Available at: https://hal.science/hal-04001745v1

Primary Keywords (Main focus):

• Rose channels in synthetic sapphire

• Synthetic sapphire inclusions

• Verneuil sapphire identification

• Twinning planes in corundum

• Gemstone identification techniques

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🔑 Secondary Keywords (Supporting terms):

• Synthetic vs natural sapphire

• Boehmite needles in sapphires

• Flame-fusion synthetic gemstones

• DiamondView gem testing

• FTIR spectroscopy in gemstones

• Corundum rose channels

• CIGTL gem testing

• Gemology sapphire features

 

Standard Gemological Instruments and their use

 

Gemological Instruments and their use

S#	Name of Instrument	Use
1	Polariscope	Polariscope is useful instrument to determine whether the stone is singly refractive (SR) or Double refractive (DR)
2	Refractometer(portable)	Refractometer is use for Refractive index (RI) of gemstone.
3	Dichroscope (portable)	Dichroscope is use for Pleochroism in gemstones. If the gemstone is pleochroic then it should be Double refractive.
4	Spectroscope(portable)	Spectroscope is use for to determine the spectrum of gemstones. With the help of spectroscope we can easily separate same colors gemstones for example ruby, red glass and garnet.
5	Ultraviolet Lamp (portable)	Ultraviolet is use for to determine Fluorescence effect in gemstones. With the help of this instrument we can separate natural blue sapphire from synthetic blue sapphire.
6	Chelsea filter (portable)	Chelsea filter is use for separating emerald from its imitations and detecting chromium in green stones and cobalt in blue stones.
7	Microscope  / Hand lens(portable)	Use for study of inclusions in gemstones. It is one of the most powerful tool in ordinary gemology tools.

 

How gemstone weight? which unit of weight is used?

Weight and price

UNIT OF WEIGHT

Ø    Gemstones are sold by weight.

Ø    Large ornamental and rough material may be sold in kilogram (Kg) or gram (gm).

Ø    Gemstone weight is given in Carats.

Ø    Carat is denoted by “Ct”       

                               1 Ct = 0.2 gm

                               5 Ct = 1.0 gm

Ø    Each carat is split into 100 cents or  points 

1.00 Ct = 100 cents or points

0.50 Ct = 50 cents or points

0.01 Ct = 1 cents or points 

Basic Terms used in Gemology

 

Basic Terms used in Gemology

Real or Natural gemstones: Real or Natural Gems are those which are entirely the product of nature and unaltered by humans in any way, except for ordinary cutting and polishing.

Treated gem: Any gem material which has been altered by humans, beyond ordinary cutting or polishing. For example Diffusion sapphire, Glass filling Ruby, dying, heat treatment etc.

 

Synthetic gems: Same as natural gem ( in terms of composition, structure, properties and appearance), except made by man. Or The Gems which have natural counterpart. For example Synthetic Ruby, sapphire etc.

How to grown synthetic quartz in laboratory by hydrothermal process?

 

Simulant or imitation: A material ( Natural or Synthetic), Which has the same appearance as the gem it imitates(look like) but different chemical composition. For example Cubic Zirconia imitating Diamond, Red Garnet is the imitation of Ruby.

 

Assembled gems or composite gems: A gem material (Natural or Synthetic), which is produced by assembling two or more pieces of the like or unlike material along a distinct junction. For example opal triplet, garnet/glass doublet.

What is gemstone? define beauty , rarity and durability in gemstone.

What is Gemstone?

Gemstone is a natural, inorganic or organic substance that has substantial beauty, rarity, and durability.

Organic Gems: An organic gem is one that was made by living things, present or past. Examples include pearls, coral, jet, ivory, shell and amber.

Inorganic Gems: Inorganic gems are those which are created by geological process and (usually) dug from the ground.

1.Beauty 2. Rarity 3. Durability

1. Beauty

 To be considered a gem, a material must possess to a large degree this preliminary qualification. Beauty in gemstone may depend on such qualities as color, transparency, luster, brilliance, pattern, optical phenomena and, in some cases, distinctive inclusions.

2.      Rarity

This is a valued attribute of gems. It is natural for man to esteem most highly the things, which are hard to obtain, and this can come about if the gemstone is simply unavailable in the marketplace, or genuinely scarce(limited or short supply) in nature, even if it does not possess qualities above others of similar beauty. A good example of this is taaffeite, which is not especially attractive, (Usually a pale reddish-violet color like some spinels), but will fetch (take) a very high price because of its rarity.

3.      Durability

Durability depends upon on three factors

1. Hardness 2. Toughness 3. Stability

1) Hardness is the ability to resist scratching. Commonly measured on the "Mohs" Scale of 1 - 10. Talc lowest (1), diamond highest (10).

Moh's Hardness scale 

Mohs hardness scale

how to grow synthetic Emerald in laboratory?

how to grow synthetic Quartz in laboratory?

2) Toughness is the ability to resist breaking or chipping. This property is measured in relative terms rather than on a numeric scale: sphalerite is fragile, diamond is moderately tough and jade is exceptionally tough. The lower the toughness of a gem the more susceptible it is to damage by the kinds of blows and knocks that are inevitable with frequent wear and use.

3) Stability is resistance to changes caused by environmental factors such as temperature, chemicals and light. Apatite is temperature sensitive, pearls are chemically sensitive, and Kunzite's color is unstable in strong light. Unstable gems exposed to common factors of the natural or man-made environment are likely to break, change color, or lose their luster.

What is mineral?

Mineral is defined as the substances which have the following catachrestic

• Naturally occurring  

• Inorganic

• Defined chemical composition

• Orderly atomic structure.

 

What is Gemology and gemologist and career prospects in gemology?

Gemology is the scientific study of gemstones. It is concerned with the study of gem materials, including identification, testing methods and the basic knowledge of crystallographic, chemical, physical and optical properties of the gemstones.

What is a Gemologist?

A gemologist is someone who can identify the gemstone with the help of Instruments. Gemologists give a business added credibility.

Career prospects in Gemology: Following are the career prospects for a Gemologist:

• Entrepreneurship in Gemstone dealing (the semi precious varieties do not cost a great deal!)
• Working as a gemologist with any of the renowned jewelers.
• Working or setting up your own laboratory for gem testing or gem identification.
• Pursuing further research in gemology or diamond grading.
• Creating your own designs in traditional or modern jewelry.
• Working as jewelry designers in fashion institutes.
• If you are a geologist you can focus your doctorate or post doctorate studies on diamonds or gemstones.
• Start with a lab setup for creating synthetic gems.
• Dealing in organic gems like corals and pearls is a different business avenue in itself.