Editing Chalcedony (section)

===Solubility===
Chalcedony is more [[soluble]] than quartz under low-temperature conditions, despite the two minerals being chemically identical. Possible reasons include the existence of the moganite component, defects caused by [[Crystal twinning|Brazil twinning]], and small crystal size.<ref name="Gislason_1993">{{cite journal |last1=Gislason |first1= S. R. |last2=Heaney |first2= P. J. |last3= Veblen |first3= D. R. |last4= Livi |first4= K. J. T. |journal=Chemical Geology |date=March 1993 |title=The difference between the solubility of quartz and chalcedony: the cause? |volume= 107 |issue= 3–4 |url= https://www.academia.edu/13667025 |pages=363–366 |doi=10.1016/0009-2541(93)90210-A |bibcode= 1993ChGeo.107..363G |access-date=2024-04-12}}</ref><ref name="heany_1992" />

====Solubility of quartz and chalcedony in pure water====
This table gives equilibrium concentrations of total dissolved silicon as calculated by ''PHREEQC'' (PH REdox EQuilibrium (in C language, USGS)) using the llnl.dat database.{{Citation needed|date=December 2009}}
{{table alignment}}
{| class="wikitable col2right col3right"
|+Comparative solubility (mg/L)
! Temperature
! Quartz
! Chalcedony
|-
!  0.01&nbsp;°C
| 0.68
| 1.34
|-
!  25.0&nbsp;°C
| 2.64
| 4.92
|-
!  50.0&nbsp;°C
| 6.95
| 12.35
|-
!  75.0&nbsp;°C
| 14.21
| 24.23
|-
!  100.0&nbsp;°C
| 24.59
| 40.44
|}