Mineral Evolution Database

Created and maintained by the Mineral Evolution Project in partnership with RRUFF and mindat.

Mineral locality data provided by mindat.org

The Mineral Evolution database is currently under development.

The goal of this page is to present localities at which the mineral is found, and estimates of the oldest possible geologic age of the minerals at these localities.

Locality Name:
Portola Valley, San Mateo Co., California, USA

mindat Locality ID: 227025
mindat URL: http://www.mindat.org/loc-227025.html

Tectonic Settings:

Total number of sublocalities beneath "Portola Valley, San Mateo Co., California, USA": 4
Total number of bottom-level sublocalities: 3

Number of Child Localities: 3
Child Localities:
El Corte De Madera Rancho
J. M. MacDonough Ranch Mine
Unnamed Pb Occurrence [1]

Latitude: 37°22'58"N
Longitude: 122°13'35"W
Decimal Degree (lat, lon): 37.382777777778,-122.22638888889

A	This mineral is Anthropogenic.
G	This mineral is directly dated.
B	This mineral is reported as having this age.
Y	This mineral is using an age reported as an element mineralization period.
O	This mineral is using an age calculated from all data at the locality.
R	The age displayed for this mineral originates from a different, non-child locality.
P	The age displayed for this mineral is the range of ages for this mineral at all of this locality's children.
	This mineral's age has not yet been recorded.

None	Quartz	Rocksalt

This Mineral list contains entries from this locality, including sub-localities. Minerals in bold are reported by mindat.org as occurring directly at this locality, and do not occur at any children (sublocalities) of this locality.

Elements at this locality, including sub-localities: Cl H Hg O Pb S Si

Elements from minerals reported directly at this locality:

Structural Groups for minerals in this locality:
None Quartz Rocksalt

6 IMA Minerals at location:

Calomel ()*	Cinnabar ()*	Eglestonite ()*	Galena ()*	Mercury ()*
Quartz ()*

Mineral name	Structural Groups	IMA Formula	# of Sublocalities containing mineral	LOCALITY IDs, not mindat ids	# of localities containing mineral
Calomel ()*	None	HgCl	1	175788	91
Cinnabar ()*	None	HgS	1	175788	2600
Eglestonite ()*	None	([Hg¹⁺]₂)₃OCl₃(OH)	1	175788	36
Galena ()*	Rocksalt	PbS	1	175790	24243
Mercury ()*	None	Hg	1	175788	397
Quartz ()*	Quartz	SiO₂	1	175789	61156

No ages have been assigned to this locality yet.

Sample	Source Locality	Reference URL

All locality data graciously provided by mindat.org

All age data...