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Summary

In this episode, Lucinda and Simon explore the fascinating world of spinel, a gemstone often overshadowed by rubies and sapphires. They discuss its chemical composition, colour variations, and historical significance, as well as the modern rise of synthetic spinel. The conversation delves into the properties that make spinel a desirable choice for jewellery, its unique inclusions, and the testing methods used to identify it. The hosts also highlight famous spinels throughout history, emphasising the gemstone's newfound recognition and value in the gemological community.

Takeaways

Spinel is often confused with rubies and sapphires due to its similar appearance.

The chemical composition of spinel is magnesium aluminum oxide.
Spinel comes in a variety of colors, including red, blue, and black.

Spinel is a durable gemstone, making it suitable for everyday wear.

Historically, spinel was often misidentified as ruby, leading to its nickname 'balast ruby.'

The Mahenge region of Tanzania produces some of the most valuable spinels.

Spinel crystals can form in octahedral shapes, similar to diamonds.

Synthetic spinel is produced using the Van Gogh flame fusion method.

Testing spinel involves using a refractometer to determine its refractive index.
Famous spinels include the Black Prince's Ruby and the Timer Ruby.

Chapters

00:00 New Year, New Beginnings
02:07 The Allure of Spinel
03:47 Understanding Spinel's Composition
07:59 The Color Spectrum of Spinel
10:55 Spinel Crystals and Their Formation
14:08 Historical Significance and Modern Sources
17:59 Inclusions and Unique Features of Spinel
18:58 Identifying Spinel vs. Other Stones
24:06 Synthetic Spinel: The Modern Challenge
30:11 Introduction to Spinels and Spectroscopy
34:03 Understanding Spinel Spectra
35:40 Famous Spinels: The Black Prince's Ruby
38:06 The Historical Significance of Spinels
41:29 The Sumerian Spinel: Myths and Legends
44:32 The Cote de Bretagne Spinel: A Unique Jewel
47:10 The Modern Recognition of Spinels

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In this episode of Facet Nation, hosts Simon and Lucinda chat with Rosie Young, a lab gemologist at GCS Lab. Rosie shares her journey from a tax advisor to a passionate gemmologist, discussing her education, experiences, and the day-to-day operations in a gem lab. The conversation delves into the fascinating world of sunstones, including their unique properties, treatments, and the science behind their colours. Rosie also highlights her research on sunstones and the importance of spreading awareness about this beautiful gemstone. The episode concludes with insights into the gem market and the joy of discovering new gemstones.

Takeaways

Rosie transitioned from tax advising to gemmology, pursuing her passion.

She graduated with a BSc in Gemmology and started working at GCS Lab.

Lab gemmology involves analysing gemstones using advanced equipment.

Sunstones are a unique and under-appreciated gemstone.

Copper-bearing sunstones come primarily from Oregon.

Diffusion treatment can alter the appearance of gemstones.

Color zoning in sunstones is a fascinating phenomenon.

Rosie enjoys sharing her knowledge about gemstones with others.

The gem market is constantly evolving with new trends.

Sunstones have a variety of localities and unique characteristics.

Titles

Exploring the World of Gemmology with Rosie Young

The Journey from Tax Advisor to Gemmologist

Sound Bites

"I always loved gems as a kid."

"It's worked out really well for me."

"I would just be happy for it."

Chapters

00:00 Introduction to Gemmology and Guest Introduction

04:39 Rosie's Journey into Gemmology

07:06 Educational Experiences in Gemmology

09:43 Internship at GIA and Research Focus

12:19 Working at GCS Lab: Daily Operations

15:11 Lab Equipment and Techniques

17:33 Trends in Gemstone Submissions

20:18 Favourite Gemstones and Unique Finds

22:46 Research on Sunstones and Their Varieties

26:14 The Quest for Sunstone Knowledge

27:18 Origins of Sunstones

28:25 Locality Preferences and Unique Characteristics

28:59 Copper-Bearing Sunstones: A Comparative Analysis

30:48 Colour Zoning in Oregon Sunstone

33:29 Copper Diffusion Experiments

36:29 The Science Behind Diffusion Treatments

38:15 Identifying Diffusion-Treated Stones

42:23 Personal Connections to Sunstone

44:59 Exploring the World of Sunstones

47:34 Inspiration from Gemstones

48:25 Holiday Greetings and Future Plans

Keywords

gemmology, sunstone, lab gemmology, gemstone treatments, GCS Lab, Rosie Young, gem education, gemstone analysis, gem certification, gem market trends

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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