Qinglong hills (Qinglongshan), Donghai
34.5150° N, 118.8961° E · ± 10 km
Quartz from Jiangsu, China, with photos of specimens from this locality.
Minerals found here
Quartz at Qinglong hills (Qinglongshan), Donghai
Rutile-needle-bearing quartz crystals that grew in veins within an ultrahigh-pressure eclogite terrane, a very different setting from typical hydrothermal quartz.
- Formula
- SiO₂
- Morphology
- Euhedral crystals containing rutile inclusions, with oscillatory growth zoning
- Associated minerals
- Coesiterutilekyaniteepidotegarnetomphacitemuscovite (phengite)
- Trace elements
- Ti (as rutile inclusions)
- History
- The quartz crystals are mined as placer material in Quaternary sediments around Donghai.
Geology of the locality
- Setting
- Sulu ultrahigh-pressure metamorphic terrane (eclogite, gneiss and quartzite); quartz crystals occur in veins in eclogite and gneiss or along their contacts, and are mined as placers in Quaternary sediments
- Type
- Hydrothermal
- Host rock
- Eclogite; orthogneiss; paragneiss; quartzite
- Region
- Jiangsu
- Country
- China
Mindat centres its grid reference on the broader area, so the position is approximate. The study on euhedral quartz crystals covers Donghai County generally rather than this single hill group.
Sources
- SRC-097 · Database
Qinglong hills (Qinglongshan), Donghai Co., Lianyungang, Jiangsu, ChinaMindat.org - SRC-098 · Article
Rutile inclusions in quartz crystals record decreasing temperature and pressure during the exhumation of the Su-Lu UHP metamorphic belt in Donghai, East China2015 · De Gruyter (journal not named on the page opened)
Draft data from the Provenite workbook. Check entries against the cited sources before relying on them. Photos are open-licence images from Wikimedia Commons; the author and licence are given with each photo.