Clay Mineral Identification Flow Diagram

X-rays of Oriented Aggregates Randomly-oriented Heated to 400oC Heated to 550oC Electron micrograph aggregate mount of clay Treated with ethylene glycol if required fraction (<2 m) Air Dried at least ½ hour at least ½ hour Results

Expands to 31-32 with Regularly interstratified chlorite- ~29 May disappear or Increases in intensity rational sequence of give 24 spacing of 24 spacing montmorillonite or chlorite- higher orders vermiculite (corrensite)

Expands May give irrational sequences May give irrational Randomly interstratified chlorite- but gives irrational sequence -- may show increase in intensity sequence montmorillonite Peaks may be broad of 12-14 peak

~14 No change No change Increases in intensity 060 near 1.54 Chlorite

060 near 1.50 Dioctahedral chlorite

No change or No change or slight Collapses to ~10 060 near 1.54 slight increase additional collapse Vermiculite

Additional collapses Slight collapse to ~12 to ~11 060 near 1.50 Dioctahedral vermiculite

No change or slight Expands to 17 Collapses to ~10 060 near 1.50 additional collapse Montmorillonite

Collapses to ~10 No change or slight 060 near 1.52 with very weak 5 peak additional collapse Nontronite

Trioctahedral montmorillonite 060 near 1.54 or vermiculite

>10-14 No change - Regularly interstratified Rational sequence of Collapses to ~10 Collapses to 10 060 near 1.54 higher orders. illite-vermiculite

No change or slight Regularly interstratified No change 060 near 1.54 increase in intensity illite-chlorite

No change - Randomly interstratified Collapses to ~10 Collapses to 10 060 near 1.54 Irrational sequence illite-vermiculite

No change or slight Randomly interstratified No change 060 near 1.54 increase in intensity illite-chlorite

Expands to Interstratified Collapses to ~10 Collapses to 10 060 near 1.50 higher spacing illite-montmorillonite

060 near 1.54 Interstratified trioctahedral illite-montmorillonite

Interstratified dioctahedral No change Slight collapse Further collapse 060 near 1.50 illite-vermiculite

Destroyed or reduced Check hkl’s 12-12.5 No change Destroyed Fibrous morphology Sepiolite in intensity against standard

Destroyed - - may Check hkl’s 10.5 No change survive slightly at Destroyed Fibrous morphology Palygorskite against standard lower temperature

060 between Illite (and/or mica), ~10 Symmetrical No change No change No change 1.51 - 1.52 muscovitic, 5 peak very various polymorphs

060 between Glauconite or 1.51 - 1.52 Celadonite 5 peak very (Roscoelite if V bearing)

060 near 1.54 Biotite various polymorphs

Interstratified Unsymmetrical or No change or illite-montmorillonite or 060 variable slight shift either way slight sharpening illite-vermiculite (Illite)

Expands to ~11 Collapses to ~7 Destroyed Tubular morphology 060 near 1.49 Endellite

Check hkl’s 7 No change No change No change Fibrous morphology Chrysotile against standard

Check hkl’s Platy morphology Antigorite against standard

060 near 1.49 Disordered kaolinite Destroyed Platy morphology hk bands present (Fireclay) moderately broad 001’s

060 near 1.54 Chlorite

Dioctahedral 060 near 1.50 Chlorite

Kaolinite Hexagonal morphology hkl’s resolved Dickite

Nacrite

Increase in spacing Collapses to 7 Destroyed Tubular morphology 060 near 1.49 Halloysite or no change hk bands present