GY 302: Crystallography and Mineralogy (2010) Lab Assignment 3: Monoclinic and Triclinic Crystallography Your Task: One last time. This is the last exercise examining elements of symmetry in crystals, point groups and stereo projections. In this lab, we will focus on the least symmetrical crystal systems; triclinic and monoclinic. Select 2 wooden crystal models from each of these 2 groups* and answer the following questions: 1) What is it's highest rotational symmetry? 2) How many mirror planes does it have? 3) How many 2 fold, 3 fold, 4 fold or 6 fold rotational axes does it have? 4) Does it have any rotoinversion axes? (2-fold and higher) 5) Does it have a center of inversion? 6) What is its point group (this will be easier than last week) 7) Draw a stick diagram for each of the models and, 8) Draw an approximate stereonet projection for each of the models In total, I expect 4 answer sheets from you (2 triclinic minerals; 2 monoclinic minerals by the due date). Make sure that you indicate the number of the model you do in the space provided on the answer sheets. Due Date: See calendar or website for due dates. * Only this time, I’m not telling you which model is which. Hint; there are more monoclinic models than triclinic models Box One Large models: 166, 167, 168, 170, 173, 184, 185, 188, 201, 204, 205, 208 Small models: 28B, 29B, 30B, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 186, 187, 188, 189, 190, 191, 192, 268, 173, 274, 275, 276 Note: Next week’s final crystallography lab quiz will have a bonus question: a 3rd wooden model drawn from either the isometric, hexagonal/trigonal, orthorhombic and tetragonal crystal classes.Monoclinic and Triclinic Models Name: _____________________________________ Date: ________________ Model Number: ___________ Crystal Class ________________ 1) How many mirror planes does it have? ____________________________________________ 2) How many 2 fold rotational axes does it have? ______________________________________ 3) How many 3 fold rotational axes does it have? ______________________________________ 4) How many 4 fold rotational axes does it have? ______________________________________ 5) How many 6 fold rotational axes does it have? ______________________________________ 6) What is the highest rotational symmetry of the model?________________________________ 7) Are any of the axes (above 2-fold) rotoinversion axes (i.e., 2 and above)?  Yes  No (indicate which on questions 2-6) 8) Does the model have a center of inversion?  Yes  No 9) What is the point group of the model? __________________________________________ Stick DiagramMonoclinic and Triclinic Models Name: _____________________________________ Date: ________________ Model Number: ___________ Crystal Class ________________ 1) How many mirror planes does it have? ____________________________________________ 2) How many 2 fold rotational axes does it have? ______________________________________ 3) How many 3 fold rotational axes does it have? ______________________________________ 4) How many 4 fold rotational axes does it have? ______________________________________ 5) How many 6 fold rotational axes does it have? ______________________________________ 6) What is the highest rotational symmetry of the model?________________________________ 7) Are any of the axes (above 2-fold) rotoinversion axes (i.e., 2 and above)?  Yes  No (indicate which on questions 2-6) 8) Does the model have a center of inversion?  Yes  No 9) What is the point group of the model? __________________________________________ Stick DiagramMonoclinic and Triclinic Models Name: _____________________________________ Date: ________________ Model Number: ___________ Crystal Class ________________ 1) How many mirror planes does it have? ____________________________________________ 2) How many 2 fold rotational axes does it have? ______________________________________ 3) How many 3 fold rotational axes does it have? ______________________________________ 4) How many 4 fold rotational axes does it have? ______________________________________ 5) How many 6 fold rotational axes does it have? ______________________________________ 6) What is the highest rotational symmetry of the model?________________________________ 7) Are any of the axes (above 2-fold) rotoinversion axes (i.e., 2 and above)?  Yes  No (indicate which on questions 2-6) 8) Does the model have a center of inversion?  Yes  No 9) What is the point group of the model? __________________________________________ Stick DiagramMonoclinic and Triclinic Models Name: _____________________________________ Date: ________________ Model Number: ___________ Crystal Class ________________ 1) How many mirror planes does it have? ____________________________________________ 2) How many 2 fold rotational axes does it have? ______________________________________ 3) How many 3 fold rotational axes does it have? ______________________________________ 4) How many 4 fold rotational axes does it have? ______________________________________ 5) How many 6 fold rotational axes does it have? ______________________________________ 6) What is the highest rotational symmetry of the model?________________________________ 7) Are any of the axes (above 2-fold) rotoinversion axes (i.e., 2 and above)?  Yes  No (indicate which on questions 2-6) 8) Does the model have a center of inversion?  Yes  No 9) What is the point group of the model? __________________________________________ Stick