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In this episode of Facet Nation, Simon and Lucinda explore the intricacies of gemmology, focusing on the polariscope and its significance in testing gemstones. They discuss the behaviour of light in relation to isotropic and anisotropic materials, the importance of understanding internal stress in gems, and the use of the conoscope for identifying gemstones. The conversation emphasises community engagement and the joy of learning in the field of gemmology.

Titles

The Fascinating World of Gemmology

Understanding Gem Testing Instruments

Sound bites

"We want to see more cats."

"Light needs to be able to get through."

"The bullseye is diagnostic of quartz."

Chapters

00:00 Introduction to Gemmology and Light Testing

02:55 Deep Dive into the Polariscope

05:26 Understanding Polarisation and Light Behaviour

08:01 Isotropic vs. Anisotropic Materials

10:41 Testing Gemstones with the Polariscope

13:05 Vibration Directions in Gemstones

15:49 Birefringence and Optical Axes

18:41 Conclusion and Key Takeaways

23:52 Understanding Polycrystalline Materials

27:19 Exploring Strain and Anomalous Double Refraction

30:39 Identifying Tabby Extinction and Writhing Snakes

34:11 The Role of the Conoscope in Gem Testing

37:26 Interference Figures: The Bullseye and Beyond

39:47 Biaxial Interference Figures and Their Significance

Understanding the importance of the polariscope in gemmology.

Light behaviour is crucial for interpreting gemstone properties.

Isotropic materials remain dark under polarised light.

Anisotropic materials show varying light responses.

Polycrystalline materials allow light through in multiple directions.

Anomalous double refraction indicates internal stress in gemstones.

Conoscopes help identify gemstone types through interference figures.

Interference figures provide diagnostic information about gemstones.

Recognising tabby extinction and writhing snakes in gem testing.

The podcast emphasises community engagement and learning.

gemmology, polariscope, isotropic, anisotropic, gemstones, light behaviour, gem testing, interference figures, conoscope, anomalous double refraction, gemology

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In this live episode of Facet nation, hosts Simon and Lucinda share their experiences at the London Gem and Mineral Show, where they discuss the fascinating gemstone Tanzanite, its properties, discovery, and significance as a birthstone for December. They delve into the science behind Tanzanite's colour, its varieties, and its cultural importance, while also sharing personal anecdotes and insights from their gemmology journey.

The London Gem and Mineral Show was a significant experience for the hosts.

Tanzanite is the birthstone for December, making it a popular gift choice.

Zoisite is the mineral family that Tanzanite belongs to.

Tanzanite's colour is influenced by the presence of vanadium and iron.

The discovery of Tanzanite is attributed to various individuals, leading to some controversy.

Tanzanite requires heat treatment to achieve its vibrant blue colour.

The gemstone is known for its vitreous lustre and unique trichroism.

Tanzanite is relatively soft, making it less suitable for certain types of jewellery.

The largest faceted Tanzanite weighs 703 carats, showcasing its potential size.

Tanzanite is associated with transformation and spirituality in various cultures.

Titles

The Fascinating World of Tanzanite

Tanzanite: A December Birthstone Exploration

Sound bites

"It's our first ever live show!"

"Tanzanite has a vitreous luster."

"Tanzanite is a very rare stone."

Chapters

00:00 Introduction to the Live Show Experience

03:16 Exploring Tanzanite: The Birthstone of December

06:19 Understanding Zoisite and Its Varieties

09:08 The Science Behind Tanzanite's Colour and Properties

12:25 The Discovery and Commercialisation of Tanzanite

15:11 Tanzanite's Unique Characteristics and Uses

18:09 Metaphysical Properties and Cultural Significance of Tanzanite

21:12 Conclusion and Future of Facet nation Podcast

Tanzanite, Gemmology, Birthstone, Zoisite, Live Podcast, Gemstones, Mineral Show, Colour Properties, Discovery, Metaphysical Properties, Gemology, Tiffany, Trichroism

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In this episode of the Facet nation podcast, Simon and Lucinda delve into the intricate world of light and optics as they relate to gemmology. They explore the fundamental properties of light, including reflection and refraction, and discuss how these principles apply to gemstones. The conversation covers the importance of cut in diamonds, the various optical effects seen in gemstones, and the significance of birefringence. The hosts also touch on the practical applications of these concepts in gem testing, providing listeners with a comprehensive understanding of how light interacts with gemstones.


Takeaways

Light is a form of electromagnetic energy that travels at high speeds.
Visible light is a small part of the electromagnetic spectrum, detectable by the human eye.
Brilliance in diamonds is a result of precise cutting and internal reflections.
The cut of a diamond significantly affects its appearance and brilliance.
Total internal reflection is crucial for maximizing light return in gemstones.
Aventurescence is caused by reflective inclusions within a gemstone.
The cat's eye effect requires specific needle-like inclusions to be visible.
Asterism is a star-like effect that requires multiple sets of inclusions.
Understanding birefringence helps in identifying different gemstone types.
The optical properties of gemstones are essential for gem testing and identification.

The Fascinating World of Gemology
Light and Optics: A Gemologist's Guide

Sound bites
"Light is a form of electromagnetic energy."
"Visible light is white."
"Brilliance is what makes diamonds special."


Chapters

00:00 Introduction to Facet nation and Light in Gemmology
03:38 Understanding Light and Its Properties
09:14 Refraction and Its Importance in Gemmology
17:39 Single vs. Double Refraction in Gemstones
23:52 Birefringence and Its Applications in Gem Testing
24:41 Understanding Light and Gemstones
28:24 The Brilliance of Diamonds
31:49 The Importance of Cut in Diamonds
34:22 Exploring Fire and Dispersion in Gemstones
37:05 Optical Effects in Gemstones
46:15 Chatoyancy and Asterism: The Star Effect
49:08 Labradoressence and Other Optical Phenomena

gemology, light, optics, reflection, refraction, birefringence, diamonds, optical effects, gemstones, gem testing, gemmology