Synthetic quartz grown in steel autoclaves under standard conditions in Na2CO3 solution (with trace Li) traps secondary phase particulates during growth. Identification of these particulates, although difficult due to small size (<5 to 100s of μm), is possible using X-ray diffraction, electron microprobe, and optical microscopic techniques. Four secondary phases were identified in normally grown crystals: Li2Si2O5, NaFeSi2O6, Na5FeSi4O12, and a phase with estimated composition Li6Na6Fe2Si18 O45. The last three phases are often found together in crystals, which suggests that a stable phase assemblage for quartz growth in steel autoclaves in Na2CO3 solution is quartz+fluid+iron oxide+NaFeSi2O6+Na5FeSi4O12+Li6Na6Fe2Si18O45. Quartz grown in Na2CO3 solution with added iron also develops three accessory phases. Quartz grown in silver liners in Li-free carbonate solution traps only NaFeSi2O6 and fluid inclusions.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Inorganic Chemistry
- Materials Chemistry