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2018/19 Undergraduate Module Catalogue

SOEE2580 Gemstones

10 creditsClass Size: 25

Module manager: Dr Dan Morgan
Email: d.j.morgan@leeds.ac.uk

Taught: Semester 2 (Jan to Jun) View Timetable

Year running 2018/19

Pre-requisite qualifications

As listed (or eqivalent for incoming study abroad students)

Pre-requisites

SOEE1570Geology 1
SOEE1580Geology 2

This module is not approved as a discovery module

Module summary

Have you ever wondered where gemstones come from? What makes them valuable? Why they have the colours that they do, and how we identify them? How are gemstones used around us in technological materials, and how are they grown in the lab? This module looks at the different gemstone families (diamond, corundums (ruby and sapphire) and beryls (emeralds)), as well as the semi-precious gemstones. The module examines all of the above in a mineralogical and geological context as well as the ethics of gemstone exploration and its effects. The module develops concepts introduced in Mineralogy and their application to gemstones as geological materials. Learn the role of the gemmologist and how to use gemmological instruments, and have the opportunity to examine genuine gemstones.

Objectives

To introduce students to the different varieties of precious and semi-precious gemstones, via consideration of their mineralogy, crystallography, origins and extraction.

Learning outcomes
The module will introduce the students to advanced topics in mineralogy through the engaging interface of gemstones. Students will discover the main classes of precious and semi-precious gems, their origins and extraction, understand the origins of colour in gemstones and crystals, and understand the techniques by which gemstones can be identified (X-ray diffraction, Spectrographs). The module is intended to have broad appeal but to drive relatively complex concepts in “hard” mineralogy using gemstones as the testbed. Example outcomes:

- Understanding The origin of colour in gemstones – valence band electrons, colour centres, quantum effects and diffraction (of light)
- How are artificial gemstones made? – methods used include Verneuil, Czochranski, and Hydrothermal cells to grow crystals.
- Diamond as a mineral – occurrence, use (industrial and domestic), igneous and metamorphic parageneses, economics and ethics
- Corundum minerals – occurrence, use (industrial and domestic), igneous and metamorphic parageneses, economics and ethics
- Beryl minerals (inc. Emeralds) – occurrence, igneous and metamorphic parageneses, economics and ethics
- Gemstone treatments – processing of gems to enhance colour and clarity, relationship to concepts of phase petrology studied in mineralogy; exsolution, inclusions and colour chemistry
- Schiller in minerals, origins and explanation, mechanics of light diffraction, relationship to feldspar structure and chemistry
- Methods to identify crystals, both destructive and non-destructive. Case study for development: X-ray diffraction, in particular the use of powder diffraction
- More gemstone treatments: irradiation, ionic implantation, fillers, triplets and oils
- Predicting gemstone behaviour and properties based upon understanding of its phase diagram.
- Exploration strategies for locating deposits: diamond example
- Gemstone provenancing using trace chemical (destructive) and optical (non-destructive) means

The module will also introduce concepts in the ethics of gemstone extraction and processing as part of the enrichment value of the course.


Skills outcomes
The module develops skills in crystallography, mineralogy and practical data gathering and analysis, such as optical spectrometry and X-Ray diffraction.


Syllabus

The syllabus is strongly connected to the outcomes detailed above. Lectures may cover such topics as:

What is a gemstone? Semi-precious stones, their characteristics and properties. Revision of basic hand specimen descriptions, introduction to various phenomena that will come back later.

The origins of colour in gemstones: The origins of the colours of various gemstones

Diamonds: origin, properties, mining and occurrence; kimberlites and xenoliths, prospecting for diamond

The corundum group: rubies and sapphires, their origin, properties, mining and occurrence

Beryls – the Emerald group, occurrence, origins, and example mines.

The syllabus will also cover aspects of gemstone treatment, handling and preparation, how they can be identified once cut, gemstone manufacture, artificial gemstones, and the economics and ethics of gemstone production.

Teaching methods

Delivery typeNumberLength hoursStudent hours
Lecture111.0011.00
Practical112.0022.00
Tutorial12.002.00
Independent online learning hours20.00
Private study hours45.00
Total Contact hours35.00
Total hours (100hr per 10 credits)100.00

Private study


There will be weekly reading assignments and also online exercises and materials to review. The coursework assessment (50%) is a short essay (1400 words) researched on a specific type of gemstone from beyond the main course, giving its composition, characteristics, economic value, origins and mode of formation, production sites and methods, ethical implications (as applicable) for production, and, if applicable, industrial uses.

Opportunities for Formative Feedback

Practical classes give a weekly contact point for feedback and assessment of progress.

Methods of assessment


Coursework
Assessment typeNotes% of formal assessment
Essay1,400 word researched essay on a named gemstone outside the main syllabus50.00
Total percentage (Assessment Coursework)50.00

Normally resits will be assessed by resit examination only unless a first attempt is granted on coursework components.


Exams
Exam typeExam duration% of formal assessment
Standard exam (closed essays, MCQs etc)1 hr 00 mins50.00
Total percentage (Assessment Exams)50.00

The exam will consist of one essay from a choice of four. If students fail the module, they can re-sit the module at the next available opportunity. The resit is by an examination of the same format as described above. This will NOT be combined with coursework grades.

Reading list

The reading list is available from the Library website

Last updated: 27/09/2018

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