Grape agate
A variety of Quartz
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About Grape agate
Formula:
SiO2
A marketing name for aggregates of spheroidal amethystine quartz/chalcedony most notably applied to material from Indonesia.
Individual spheres measure 2 to 20 millimeters in diameter and consist of thin radially grown "fibers" made of quartz.
In spite of this spherulitic growth pattern, thin sections show that this is not agate (Laurs & Rossman, 2018).
Colour can range from deep purple to very pale amethystine or whitish shades.
There are also less commonly green ones (colored by inclusions of some clay mineral), and even specimens with purple and green spherules together.
Poorly coloured specimens sometimes get dyed violet.
Individual spheres measure 2 to 20 millimeters in diameter and consist of thin radially grown "fibers" made of quartz.
In spite of this spherulitic growth pattern, thin sections show that this is not agate (Laurs & Rossman, 2018).
Colour can range from deep purple to very pale amethystine or whitish shades.
There are also less commonly green ones (colored by inclusions of some clay mineral), and even specimens with purple and green spherules together.
Poorly coloured specimens sometimes get dyed violet.
Unique Identifiers
Mindat ID:
51479 (as Grape agate)
3337 (as Quartz)
3337 (as Quartz)
Long-form identifier:
mindat:1:1:51479:4 (as Grape agate)
mindat:1:1:3337:0 (as Quartz)
mindat:1:1:3337:0 (as Quartz)
Chemistry of Grape agate
Mindat Formula:
SiO2
Elements listed:
Synonyms of Grape agate
Common Associates
Associations Based on Photo Data:
| 9 photos of Grape agate associated with Quartz | SiO2 |
| 7 photos of Grape agate associated with Celadonite | K(MgFe3+◻)(Si4O10)(OH)2 |
| 2 photos of Grape agate associated with 'Amethyst' | SiO2 |
| 2 photos of Grape agate associated with 'Chalcedony' | SiO2 |
| 2 photos of Grape agate associated with Calcite | CaCO3 |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Grape agate
mindat.org URL:
https://www.mindat.org/min-51479.html
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References for Grape agate
Localities for Grape agate
Showing 1 localities.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
Struck out - Mineral was erroneously reported from this locality.
Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Indonesia | |
| Ivey (2018) |
"Grape Agate" mines, Mamuju Regency, West Sulawesi Province, Indonesia