Geology 221a - Mineralogy

Mineral Characterization Project

Each student is required to prepare a report (term paper) presenting data obtained for a mineral, possibly collected on one of the class field trips. There are lots of rock samples available that you might use. The report should include a brief description of the locality from which the mineral was collected, including references to published work on the locality if published work exists. Any implications that the presence of the selected mineral has for the geologic history of the locality should be noted, again citing the appropriate literature.

Although the choice of the mineral is yours, there are some restrictions. The mineral must be a silicate or simple oxide (e.g. not calcite or sphalerite). The mineral must be part of a solid solution series (e.g. not quartz). It cannot have cubic symmetry (e.g. not garnet or fluorite). It must be optically transparent (non-metallic luster). It must be from a rock, not just an isolated mineral specimen out of context. Good minerals to choose from include: olivine, epidote group minerals, orthopyroxene, clinopyroxene, orthoamphibole, clinoamphibole, calcic amphibole, sodic amphibole, white mica, biotite, alkali feldspar, plagioclase feldspar. Other minerals are also possible, but please get your mineral approved before proceding.

The types and quantity of data collected will be determined in part by the specific mineral being studied, but the data presented should include: (1) hand specimen physical properties and photo, (2) optical properties including refractive indices, (3) powder diffraction data including major diffraction lines, relative intensities of those lines, Miller indices of those lines, space group, and all unit cell parameters, (4) the chemical composition of the mineral, a formula calculated from the composition, and a graphical representation of the composition relative to the solid solution series of the mineral, (5) information about the synthesis and stability of the mineral, including a description of your own synthesis or decomposition experiments. Some of these data will be collected as part of lab assignments during the semester. Lab reports may be appended, but the data should be shown in a new table or tables. Figures should be appropriately labeled and be accompanied by a caption. Your new data should be placed in the (literature) context of what is known about the mineral in general. For example, a brief description of the crystal structure is expected (an illustration -- CrystalMaker? -- will help), including a list of the major crystallographic sites with their coordination numbers and probable occupancy for your sample.

Wherever possible, the information reported should be quantitative rather than qualitative. Be sure to give the appropriate units for all measurements. Uncertainties should be listed for all measurements. Describe enough about the measurement procedures so that the reader might attempt to reproduce your results. However, do not describe textbook procedures such as how to use a Becke line or orient a spindle stage. Brief technical information on the major instruments and software is appropriate.

Clarity of presentation is essential. Illustrations and data tables will be needed and should be included as an integral part of the paper. Please append any appropriate supporting documents, such as computer printouts. However, the reader should not be expected to look at the printouts to find important data.

All reports should be submitted in the style of an American Mineralogist article as detailed in that journal (volume 72, p. 1043-1049) or on the WWW (http://www.minsocam.org/MSA/AmMin/instructions.html). The paper should begin with an abstact that is a summary of the paper that contains the important data. Note that only references cited in the paper should be in the list of references; a bibliography is not to be included.