Archstone, Agoura Hills, Los Angeles County, California, USAi
| Regional Level Types | |
|---|---|
| Archstone | Occurrence |
| Agoura Hills | City |
| Los Angeles County | County |
| California | State |
| USA | Country |
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Latitude & Longitude (WGS84):
34° 8' 17'' North , 118° 47' 33'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Westlake Village | 8,507 (2017) | 1.5km |
| Agoura Hills | 20,915 (2017) | 1.7km |
| Agoura | 20,537 (2006) | 5.1km |
| Oak Park | 13,811 (2011) | 5.3km |
| Thousand Oaks | 129,339 (2017) | 5.5km |
Nearest Clubs:
Local clubs are the best way to get access to collecting localities
Local clubs are the best way to get access to collecting localities
| Club | Location | Distance |
|---|---|---|
| Conejo Gem & Mineral Club | Thousand Oaks, California | 5km |
| Del Air Rockhounds Club | Northridge, California | 26km |
| Oxnard Gem & Mineral Society | Oxnard, California | 36km |
| Sierra Pelona Rock Club | Newhall, California | 36km |
| The Culver City Rock and Mineral Club | Culver City, California | 39km |
This locality has similar geology to the rest of the Ladyface Mtn area, including marcasite agate and chalcedony in brecciated volcanic rock, mainly andesite. The difference here is the fact that some of the marcasite oxidized into secondary minerals including jarosite, sulfur and gypsum. This is the third occurrence of jarosite and the first confirmed occurrence of elemental sulfur in Santa Monica Mts.
Jarosite occurs as dark brown flat trigonal bipyramid crystals up to 3mm in size throughout the vugs in the white agate. Second-generation jarosite frequently occurs on top of the brown jarosite in sparkly masses of honey yellow color, it is sub-mm size. Sulfur occurs as bright light-yellow sharp euhedral crystals up to 2mm. White powdery gypsum shows up occasionally, in a few places as mm-size euhedral gypsum crystals. Some of the vugs contain bubbly chalcedony covered with strongly iridescent goethite. Vugs exposed to the elements usually contain orange and red limonite.
The area also yielded angelwing agate, lots of gray chalcedony and some quartz crystals that exhibit weird stacks of almost rhombohedral shape crystals.
There is an outcrop a little bit farther off the trail with melanophlogite pseudomorphs in chalcedony vugs in brecciated volcanic rock.
The samples were analyzed by Dr. Housley.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsMineral List
Mineral list contains entries from the region specified including sub-localities6 valid minerals.
Detailed Mineral List:
| ⓘ Goethite Formula: Fe3+O(OH) References: |
| ⓘ Jarosite Formula: KFe3+3(SO4)2(OH)6 References: |
| ⓘ 'Limonite' References: |
| ⓘ Marcasite Formula: FeS2 References: |
| ⓘ Native Sulphur Formula: S8 References: |
| ⓘ Opal Formula: SiO2 · nH2O References: |
| ⓘ Quartz Formula: SiO2 |
| ⓘ Quartz var. Agate Formula: SiO2 References: |
| ⓘ Quartz var. Chalcedony Formula: SiO2 |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Native Sulphur | 1.CC.05 | S8 |
| Group 2 - Sulphides and Sulfosalts | |||
| ⓘ | Marcasite | 2.EB.10a | FeS2 |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Goethite | 4.00. | Fe3+O(OH) |
| ⓘ | Quartz var. Agate | 4.DA.05 | SiO2 |
| ⓘ | var. Chalcedony | 4.DA.05 | SiO2 |
| ⓘ | 4.DA.05 | SiO2 | |
| ⓘ | Opal | 4.DA.10 | SiO2 · nH2O |
| Group 7 - Sulphates, Chromates, Molybdates and Tungstates | |||
| ⓘ | Jarosite | 7.BC.10 | KFe3+3(SO4)2(OH)6 |
| Unclassified | |||
| ⓘ | 'Limonite' | - | |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Goethite | Fe3+O(OH) |
| H | ⓘ Jarosite | KFe33+(SO4)2(OH)6 |
| H | ⓘ Opal | SiO2 · nH2O |
| O | Oxygen | |
| O | ⓘ Quartz var. Agate | SiO2 |
| O | ⓘ Quartz var. Chalcedony | SiO2 |
| O | ⓘ Goethite | Fe3+O(OH) |
| O | ⓘ Jarosite | KFe33+(SO4)2(OH)6 |
| O | ⓘ Opal | SiO2 · nH2O |
| O | ⓘ Quartz | SiO2 |
| Si | Silicon | |
| Si | ⓘ Quartz var. Agate | SiO2 |
| Si | ⓘ Quartz var. Chalcedony | SiO2 |
| Si | ⓘ Opal | SiO2 · nH2O |
| Si | ⓘ Quartz | SiO2 |
| S | Sulfur | |
| S | ⓘ Jarosite | KFe33+(SO4)2(OH)6 |
| S | ⓘ Marcasite | FeS2 |
| S | ⓘ Native Sulphur | S8 |
| K | Potassium | |
| K | ⓘ Jarosite | KFe33+(SO4)2(OH)6 |
| Fe | Iron | |
| Fe | ⓘ Goethite | Fe3+O(OH) |
| Fe | ⓘ Jarosite | KFe33+(SO4)2(OH)6 |
| Fe | ⓘ Marcasite | FeS2 |
Localities in this Region
- California
- Los Angeles County
- Agoura Hills
- Archstone
- Agoura Hills
- Los Angeles County
Other Regions, Features and Areas containing this locality
North AmericaContinent
- Coast MountainsMountain Range
North America Plate
- California BorderlandAccretionary Complex
- Franciscan DomainDomain
- Southern California Borderland BasinsBasin
Pacific PlateTectonic Plate
USA
- California
- Santa Monica MountainsMountain Range
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References
Archstone, Agoura Hills, Los Angeles County, California, USA