EOSC118 Sketching Activity 1: Beryl Crystal Structure

The canvas below shows two views of the crystal structure for beryl (chemical formula Be3Al2Si6O18). Based on the relative abundances of cations in the mineral formula, follow the steps given below to label or sketch these features:

  1. The polyhedra that represent SiO4 groups
  2. The polyhedra that represent BeO4 groups
  3. The polyhedra that represent AlO6 groups
  4. The location of basal cleavage
  5. The location of the structure's channels
  6. Your student number and name!

Follow the detailed numbered steps below the sketching canvas to complete the activity
*if the canvas doesn't load, see the TIPS at the bottom of the page.

Detailed steps:

  1. Click the "Stroke" colour button (near the bottom left) to pick a text color (e.g., black). This sets the colour being used.
  2. Click the "Text" tool (looks like Aa) and type your student number and name (e.g., 12345678 David Turner) in the dialogue box that appears. Click, hold, and place to add the text at the top next to "Name__" and on top of the crosshatch pattern. If you make a mistake, you can use the "Undo Arrow" button, or the "Eraser" that will only affect what you have added, not the underlying canvas.
  3. First we'll annotate two SiO4 polyhedra - they can be on either viewing angle (top or bottom).
    1. Use the "stroke" to pick a color close to that of the SiO4 polyhedra in the figure.
    2. Type SiO4 and place this in an unambiguous location that clearly identifies the group of polyhedra. Do this again for another SiO4 polyhedron.
  4. Repeat this step (pick specified colour and annotate) to identify two polyhedra that represent BeO4.
  5. Do this a third time to identify two polyhedra that represent AlO6.
  6. Beryl shows good basal cleavage. Show where this plane is most likely to exist by using the "line" tool, with the colour of the "stroke" as black, and the "dashed line" option. Make sure your line is drawn parallel to the cleavage plane, and label the line as “cleavage” with black text.
  7. Beryl has channels along its c-axis within which water and other cations and anions can reside. Draw a solid black arrow pointing to the centre of one of these channels. Label the arrow with the word “channel” using black text.
  8. Double check that your student number and name are present on the image.
  9. Now save your work so it can be uploaded to Connect. DO NOT SIMPLY PRINT-SCREEN, use the following procedure:
    1. Click "Export as PNG button (under tools). This puts your result in a new browser tab.
    2. Use your browser to "Save as" or "Save Image As" (typically by right-clicking the image).
    3. PLEASE name this file using your student number and name: e.g., "12345678JaneDoe.png". Do NOT change the "png" part.
  10. Finally, upload your image to the Course CONNECT site as instructed in the CONNECT assignment.

Once you have submitted your image WITH FILE NAME AS INSTRUCTED ABOVE, you are done!


Creative Commons License EOSC 118 Beryl crystal activity by D. Turner, F.Jones.
Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.