Topic
The Mineral Beryl
Instructions
1.What is the difference between crystals, minerals and rocks?
2.a) Diamond and graphite are said to be polymorphs. Define polymorph.
b) Describe (or sketch) the crystal structures of diamond and graphite.
c) How do their different structures impact their perceived colour?
3. (Malachite and azurite samples can be found in numerous Gallery Sections)
a) Malachite and azurite are pseudomorphs. Define pseudomorph.
b) State their colours, and the metal common to both, and the chemical formula for each.
c) If malachite and azurite are so closely related chemically, why do their colours differ so
much?
4. a) Complete the following table, stating the fluoresced colour for each mineral:
Mineral Fluoresced colour
Hyalite (No. 1)-
Calcite (No. 4)-
Calcite (No. 12)-
Meiomite (No. 14)-
b) How does the process of fluorescence occur? Why to the fluoresced colours of the above minerals differ?
5 Silicates contain variations on the basic tetrahedral structure of SiO4.Depending, on the arrangement, different families of silicates are obtained.
Sketch the basic tetrahedral structure of SiO4.
Fill in the following table, describing the structure of various types of silicates (can sketch and scan, or describe the structure in words):
Type of silicate Structural arrangement of SiO4 mineral example
Neosilicates
Sorosilicates
Cyclosilicates
Inosilicates
Amphiboles
Phyllosilicates
Tectosilicates
Colour in Minerals and Gems
6 a) What is the difference between an idiochromatic and an allochromatic mineral?
b) Smithsonite is allocromatic. What colour variations do you see? What is its chemical formula?
c) Describe the appearance of cinnabar. What chemical element is it derived from? Which pigment is made from it?
d) How do inclusions give rise to colour in some minerals? Give an example of a mineral which is coloured via inclusions.
7. Gemstone gallery
Describe the colours(s) and appearance of your 3 favourite gemstones.
Write a 4-5 page (12-point, double spaced, plus figures and references) essay on your gemstone/mineral. Include the following information:
-introduction and general overview (0.5 page)
-the colour producing mechanism (1-2p)
-if there are variations in colour – physically how those variations are produced (0.5-1p)
-a diagram of the crystal structure and/or molecular composition
-specific uses for that mineral/gem (1p)
-conclusion (0.5p)
-References and in text citations in proper format (eg APA or MLA)
Suggested minerals/ gemstones: (can choose others)
sapphire, ruby, topaz, tourmaline, opal, emerald, malachite and azurite, beryl, coloured diamonds (can do specific colour – e.g. blue diamonds), amethyst.
Answer preview
Beryl is a mineral that occurs in a variety of colours and other physical features. The colour of Beryl can range from colourless to translucent colours because of the presence of impurities. The common colours of Beryl include blue, green, and yellow, white and green (Wenk & Bulakh, 2016). Beryl often exists in hexagonal crystalline form and can have some fractures. Beryl crystal sizes range from small to large sizes, up to a few meters in width. The uses of Beryl rest with its role as a primary ore of some metals such as beryllium and the variety of Beryl implies different uses.
Word count: 1278