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Table 1 Sample summary with information on crystalline silica features observed by Horwell et al. [12]

From: The structure of volcanic cristobalite in relation to its toxicity; relevance for the variable crystalline silica hazard

Sample No. Date of collapse/eruption Date of collection Description Eruption Information Crystalline silica type
Prismatic Platy Devit. cristob. Devit. quartz.
Dome rock:
MVO819 174 k.a. BP 15/2/98 Dome lava; very dense, grey/brown Ancient sample from old complex but rare
MVO945 400 a BP ? Dome lava; Dense, red/brown Ancient simple from Castle Peak × ×
MVO287 21/9/97 21/9/97 Juvenile block; vesicular; light grey From dome collapse deposit × ×
MVO288 21/9/97 21/9/97 Juvenile block; frothy, light grey From dome collapse deposit but rare × × ×
MVO617 21/9/97 16/5/98 Dome lava; Dense; Green/dark grey From dome collapse deposit × ×
MVO332 26/12/97 4/1/98 Dome lava; Vesicular; pale grey From 'Boxing Day' collapse deposit × × ×
MVO1236 12/7/03 1/8/03 – 15/11/03? Dome lava; Dense; pale grey From dome collapse deposit (full collapse)
MVO1406 20/5/06 ? Dome lava; dense; pale grey From dome collapse deposit × ×
MontR1* 20/5/06 22/6/06 Dome lava, dense, altered, red From dome collapse deposit ×
MRA5/6/99 05/6/99 05/6/99 Co-PDC ash Respirable (< 4 μm) fraction  
MBA12/7/03 12/7/03 12/7/03 Co-PDC ash Bulk ash from which cristobalite separated  
  1. ‘Prismatic’ = euhedral cristobalite; ‘Platy’ = platelets of cristobalite; ‘Devit. cristob.’ = cristobalite during glass devitrification; ‘Devit. quartz’ = quartz formed (probably through phase transition from cristobalite) when the glass is totally devitrified.
  2. *Collected by BW from deposit rather than archive.
  3. MVO sample numbers assigned by the Montserrat Volcano Observatory.