Image: <bdi><a href="https://www.wikidata.org/wiki/Q56247090" class="extiw" title="d:Q56247090"><span title="mineral collector and dealer">Robert M. Lavinsky</span></a></bdi> (CC BY-SA 3.0)
orthorhombicuncommonOxides
Columbite
(Fe,Mn)Nb2O6
A dark, blocky, submetallic crystal, likely black or very dark brown, with a somewhat rectangular or tabular habit, measuring approximately 3.5 cm.
Columbite Physical Properties
Mohs Hardness
6Crystal System
orthorhombicLuster
vitreousStreak Color
dark red to blackCleavage
good in one direction ({100})Fracture
subconchoidal to unevenSpecific Gravity
6Colors
black, brownish-black, dark brownTransparency
opaqueType Locality
Middletown, Middlesex County, Connecticut, USAMineral Group
OxidesUses
source of niobium, collector's specimensAssociated Minerals
quartz, feldspar, mica, beryl, tourmaline, spodumene, cassiterite, tantaliteRarity
uncommonGeological Context
Columbite typically forms in granite pegmatites and is often associated with other rare-earth minerals. It can also be found in placer deposits.
