Minerals, Rocks & Microscope
Teacher Guide
Unit assessment requirements
The Minerals & Rocks Higher Geology unit (D8XH 12) includes work on the identification
of minerals and rocks under the microscope. Until this year it formed part of the practical
work required for the unit. However changes in SQA’s Conditions & Arrangements for
Geology Higher have led to the removal of the need to carry out the practical assessments
on rock and mineral identification under the microscope. It is still, however, a vital
element in the Minerals & Rocks unit and package has been left as an assessment tool in
case the practicals are reinstated at a later date.
The use of the package ‘Minerals, Rocks & Microscope’
A petrological microscope is an expensive piece of equipment and few teachers have
access to more than one; some indeed may have none. It is also very difficult, when
teaching microscopic work, to know whether a student is actually seeing what he/she is
expected to observe, or even that the student has focused on the slide correctly.
This package - Minerals, Rocks & Microscope – has been designed to help overcome
these problems, though it cannot replace the captivating reality of viewing a rock through
the petrological microscope for the first time. The ability to rotate the stage is lost and any
colour changes on rotation cannot be appreciated. These colour changes are important
diagnostically when it comes to testing for the presence of pleochroism or for the
maximum polarisation colour of a mineral. However having seen the real thing, it is easier
to visualise from the still image what might happen when the stage is rotated.
What ‘Minerals, Rocks & Microscope’ contains:
The package is designed as both a teaching pack and an assessment tool. It includes the
following files:
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Power-Point presentations:
The Petrological Microscope
Minerals under the Microscope
mineral test 1
mineral test 2
Word documents:
Mineral Assessment H. Geology
key to minerals under microscope
Teacher Guide
Rocks under the Microscope
rock test 1
rock test 2
Rock Assessment H. Geology
key to rocks under microscope
Most magnifications used are X30 (30 times) and students should be made aware of that.
Advice on use of teaching materials :
It is strongly recommended that all students be introduced to the use of a petrological
microscope. This prepares them better for when it comes to viewing the presentations of
minerals and rocks provided in this package.
Students should start with the study of minerals using the document ‘Minerals under the
Microscope’. Work on the program can be done individually or as a whole class
exercise, via the use of a projector; either way the teacher/lecturer would need to go over
various points relating to the use of the program and to the identification of mineralogical
features. It may be best to do this as a class exercise first and then let the students work
through it on their own. Once the students have grasped the basics, the test can be
given.
The teacher can choose either mineral test 1 or 2 and conduct it as a whole class or let the
students work at it individually if sufficient PCs are available. Each student needs to be
issued with a copy of the ‘Mineral Assessment Higher Geology’ which they complete as
the program runs and the ‘key to minerals under microscope’ which they need for
reference. A pass requires the correct identification of 7 out of 10 minerals. A
reasonable quality of description relating to each mineral is essential, although there will
be items that do not apply in some cases – e.g. extinction angle does not apply to quartz
or pleochroism to muscovite. Teachers are free to adjust the assessment sheets to
include candidate number and name and number of centre. There is no time limit on the
completion of the exercise, but a double period would be more than sufficient if done as a
class exercise.
Students should then move on to the study of rocks using the document ‘Rocks under the
Microscope’. The procedure should be the same as for the minerals. A pass in the
rocks element requires the correct identification of 8 out of 11. Again descriptions should
be thorough.
It is important that all students are made aware of how to work through the
programs before any testing is done.
George Strachan
October 2005