Material
Two minerals
Quartz surrounds the rutile needles. Their separate chemistry remains part of the same stone.
Stone Explorer → Golden rutilated quartz comparison tool
Golden rutilated quartz, side by side.
Compare 4 natural specimens with golden rutile needles, then follow one way quartz can grow around them.
All golden rutilated quartz pieces →
Golden rutilated quartz · 4 natural specimen records
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Each specimen opens its own file.
Evidence
Needles, host and record.
Compare the visible needles. Read identity and locality in the specimen file.
Appearance
Density and direction
Compare crossed needles, denser bundles and clear spaces. These are visible patterns within a specimen.
Records
Identity and locality
The source identifies each specimen and gives its locality. Treatment and geological age are unrecorded.
Sources
Sources & specimen records.
Mineral descriptions, locality reports and photograph records.
Quartz and rutileMaterial and evidence
Golden rutilated quartz describes quartz containing golden-looking rutile inclusions. Needle colour and shape alone are insufficient to identify an unknown inclusion.
Handbook of Mineralogy: Quartz · Handbook of Mineralogy: Rutile
Locality and geological timeMaterial and evidence
GIA documents golden rutilated quartz mining around Remédios, Novo Horizonte, Bahia. That regional report is separate from the locality labels of these specimens. A dated mineralisation event applies to the material studied.
Ibitiara groupCC BY-SA 3.0
Didier Descouens, Wikimedia Commons · CC BY-SA 3.0
Resized and compressed proportionally; colours unchanged. Card crop; full photograph in the file. Image derivatives: CC BY-SA 3.0.
Ibitiara pointCC BY-SA 3.0
Rob Lavinsky, iRocks.com, Wikimedia Commons · CC BY-SA 3.0
Resized and compressed proportionally; colours unchanged. Card crop; full photograph in the file. Image derivatives: CC BY-SA 3.0.
Nalps ValleyCC BY-SA 3.0
Rob Lavinsky, iRocks.com, Wikimedia Commons · CC BY-SA 3.0
Resized and compressed proportionally; colours unchanged. Card crop; full photograph in the file. Image derivatives: CC BY-SA 3.0.
Formation drawingOne possible pathway
The cutaway follows one possible sequence in which quartz encloses earlier rutile. Other growth relationships occur. The cavity and enlarged detail are schematic and describe no particular deposit.
Needle density and arrangementMaterial reference
Sparse needles, dense bundles, parallel sets, crossings and radiating stars describe rutile arrangements inside quartz. One crystal can contain several arrangements. Golden needles and the colour of the quartz host are separate observations; smoky quartz can also enclose rutile.
Open sourceA needle star and an optical starMaterial reference
A radiating needle star stays fixed inside the crystal. Chatoyancy is a moving band of light; asterism forms intersecting light bands. These optical effects require suitable inclusion alignment and viewing geometry, often revealed by a curved cut. A star-shaped needle photograph proves neither effect. Rutile may grow with hematite, which needs its own specimen evidence.
Open sourceIdentity and sequenceMaterial reference
Copper-red, silver-looking, black and green threads in quartz are appearance descriptions. Colour alone does not identify rutile. Some inclusions predate their quartz host; others grow with it. Later fractures can admit a further generation of minerals. The sequence must follow the observed relationships in each specimen.
Open source
