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Explore the fascinating world of physical optics in gemstones, focusing on iridescence, thin film interference, and the science behind colour phenomena like labradorescence and opalescence. Perfect for budding gemologists and enthusiasts alike.

key topics
Physical optics in gemstones
Iridescence and wave interference
Thin film interference in gem materials

Unveiling Gemstone Colours: The Science of Iridescence and More
The Hidden Physics of Gemstone Beauty: A Deep Dive


sound bites
"Iridescence is caused by wave interference."
"Labradorescence is due to the chemistry of feldspar."
"Pearlescence results from stacked layers of aragonite."


Chapters
00:00 Introduction to Physical Optics
02:09 Understanding Iridescence
11:00 Exploring Twin Planes and Their Effects
14:11 The Fascination of Labradorescence and Adularescence
20:03 The Nature of Light and Colour
21:06 Exploring Rainbow Moonstone
22:28 The Allure of Pearls
25:06 Understanding Iridescence in Pearls
28:27 The Mystique of Opals
36:52 Reflections on Quality and Value in Gemstones

resources
Facet Nation Podcast - https://youtube.com/@facetnationuk


guest links
Instagram - https://instagram.com/facetnationgemmology
TikTok - https://tiktok.com/@facet.nation.pod
Email - mailto:facetnation@facetnation.co.uk

gemmology, physical optics, iridescence, labradorescence, opalescence, gemstone science, thin film interference, gemstone phenomena

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This episode explores the fascinating world of coral, its history, types, and significance in gemmology. Hosted by Simon and Lucinda, it covers everything from the biological origins of coral to its cultural importance and modern regulations.

sound bites

"Polyps are tiny creatures related to sea anemones."

"Coral structures are like a living family tree."

"Black and gold coral are rare and often bleached."

key topics

Definition of organic materials

History of coral harvesting and trade

Types of coral: precious, soft, fossilised, black and gold

Identification and authenticity of coral in jewelry

Regulations and sustainability in coral trade

Chapters

00:00 Introduction to Coral and Organic Materials

02:53 The Importance of Organic Materials

05:14 Coral Fishing in History

07:57 Understanding Coral Polyps

10:32 The Journey of Coral Harvesting

13:03 Regulations and Sustainability in Coral Harvesting

15:33 Coral as a Jewelry Material

18:03 Types of Coral and Their Significance

21:50 Identifying Coral: Key Features and Characteristics

24:33 Understanding Soft Coral: Misleading Names and Textures

26:42 Fossilised Coral: The Transformation Process

28:20 Exploring Black and Gold Coral: Unique Properties and Origins

32:17 Coral Conservation: The Impact of Overfishing and Regulations

34:44 Closing Thoughts: The Beauty and Importance of Coral

resources

Gemmology by C. D. M. Roberts - https://www.amazon.com/Gemmology-C-D-M-Roberts/dp/XXXXXX

CITES - Convention on International Trade in Endangered Species - https://cites.org/

Coral Museum in Naples, Italy - https://www.coralmuseumnaples.it/

https://instagram.com/facetnationgemmology

guest links

Instagram - https://instagram.com/facetnationgemmology

TikTok - https://tiktok.com/@facet.nation.pod

coral, gemmology, organic materials, jewellery, coral harvesting, coral types, coral regulation, fossilised coral, coral history, coral identification

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In this episode, Lucinda and Simon explore the fascinating world of gemmology instruments, focusing on colour filters like the Chelsea colour filter and pleochroism testing methods. Learn how these tools aid in gemstone identification and enhance gem cutting techniques.

Educational

key topics

Colour filters in gemmology

Chelsea colour filter purpose and use

Pleochroism and its significance in gemstone identification

Testing for pleochroism with London Dichroscope and calcite dichroscope

Importance of light source and gemstone orientation in testing

Natural vs synthetic gemstone identification techniques

key frameworks

Colour absorption principles

Pleochroism and optical anisotropy

Gemstone orientation and cutting strategies

Titles

Mastering Gemstone Identification: The Power of Colour Filters and Pleochroism Tests

Unlocking Gem Secrets: Chelsea Filter and Pleochroism in Gemmology

sound bites

"Record your observation by stating the colour scene."

"Always think about why you're looking at the stone."

"Share your pleochroic observations with others."

Chapters

00:00 Introduction to Colour Filters in Gemmology

01:55 Understanding Pleochroism and Selective Absorption

05:27 Testing for Pleochroism with the London Dichroscope

10:34 Comparing the London Dichroscope and Calcite Dichroscope

15:36 Documenting Pleochroism Observations

17:35 Understanding Gemstone Colours and Pleochroism

20:04 The Chelsea Colour Filter: A Gemstone Testing Tool

26:23 Practical Applications of the Chelsea Colour Filter

28:50 Identifying Gemstones: Colour Responses and Observations

resources

Gem-A - https://www.gem-a.com

Pleochroism in Gemstones (Book) - https://www.amazon.com/pleochroism-gemstones

Instagram - https://www.instagram.com/facetnationgemmology

Email - facetnation@facetnation.co.uk

gemmology, colour filters, Chelsea filter, pleochroism, gemstone identification, gem testing, gem cutting, gemmology tools

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