1. X-ray Diffraction (XRD) and Forensic Geology X-ray diffraction pattern for goethite X-ray diffractometer (XRD) laboratory

2. Structure of minerals Structure of minerals Minerals consist of an orderly array of atoms chemically bonded to form a particular crystalline structure. Internal atomic arrangement in ionic compounds is determined by ionic size.

3. Geometric packing of various ions Figure 3.8

4. Crystal Lattice: the three dimensional molecular structure of a mineral. (Shape of the “unit cell.”) the various ions that make up the mineral. Geometry + chemistry! Structure of Minerals

6. Halite (rock salt) Structure of Minerals

7. Diagram illustrating Bragg’s law.  = angle of incidence and diffraction when Bragg’s law conditions are met. d = inter-planar spacing.

8. Bragg’s Law λ = 2d(sinθ) where: λ = x-ray wavelength d = spacing between planes of atoms in crystal  θ = x-ray incidence angle (Bragg angle) also: d = λ /2sin θ sin θ = λ /2d

11. XRD Laboratory