Log InRegister
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsBooks & Magazines
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsUsersMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryMineral Photography

Mill Rock, Hamden, New Haven Co., Connecticut, USA

This page is currently not sponsored. Click here to sponsor this page.
Mill Rock is a diabase intrusive forming a 3/4-mile long, E-W trending ridge cross-cutting the Triassic New Haven Arkose. Mineralization was reported in a small quarry at the west end. Dana (1877) reports on the initial find:

"[Garnets] occur on the line of contact between the trap and the adjoining sandstone, and probably owe their origin to the metamorphic action of the heat of the erupted rock. They are found best in seams and little cavities in the trap, where they are implanted as isolated crystals upon an earlier deposit of quartz crystals. Occasional garnets of indistinct crystalline form but presumably of similar origin occur on the surfaces of the sandstone adjoining; scales of hematite produced by metamorphic action are common on the same surfaces."

At the eastern end of the ridge, Eaton (1927) reports that a small quarry (Powder Hill Quarry) uncovered prehnite and copper mineralization.

Mineral List

10 entries listed. 8 valid minerals.

The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


Dana, Edward S. (1877): On the occurrence of Garnets with the Trap of New Haven, Connecticut. American Journal of Science Series 3, Volume 14, page 215.

Eaton, Frederick S. (1927): Mineral Localities of Connecticut. Rocks & Minerals, vol. 2, no. 4, pp. 141-2.

Longwell & Dana. (1932): Walks & Rides in Central Connecticut and Massachusetts. p.228.

Mineral and/or Locality  
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Public Relations by Blytheweigh.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2020, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: January 22, 2020 07:55:58 Page generated: January 14, 2015 15:18:41
Go to top of page