Goethite is an iron oxyhydroxide containing ferric iron. It is the main component of rust and bog iron ore. Goethite's hardness ranges from 5.0 to 5.5 on the Mohs Scale, and its specific gravity varies from 3.3 to 4.3. The mineral forms prismatic needle-like crystals ("needle ironstone" [3]) but is more typically massive. [2]

This specimen shows fibrous goethite with concentric banding in shades of brown and yellow, along with sugary quartz. It came from Restormel Royal Iron Mine, and was probably acquired shortly after the royal visit. Chemical Formula: Fe 3+ O(OH) Specimen no. TRURI: 801.1047 Location: Restormal Royal Iron Mine, Lostwithiel Grid Reference: SX 098 614

Almost dendritic, treelike formations coming off the piece in opposing directions along one plane distinguish this Goethite specimen. There are several hollow areas, and one or two smooth edges that signify the former presence of long, prismatic selenite crystals.

Goethite is a widespread mineral in the iron ranges of the Northern Peninsula, and as an alteration product of iron-bearing minerals in rocks throughout the state. Goethite typically forms under supergene oxidizing environments by weathering of …

Throughout the 150 years of history, it has produced a wealth of mineral specimens, including azurite, malachite, chrysocolla, dioptase, copper, cuprite, and more! Read More Aug 26, 2024

Elongate well formed crystals of Goethite are scattered over, and intergrown with, sharp prismatic Quartz crystals to create a vuggy 3-D specimen. The Goethite crystals are very lustrous metallic grey, measuring to 6mm length. They are well formed with striations along the length of the crystal and some crystals are doubly terminated. The ...

Goethite is a metallic-grey, iron-bearing mineral that frequently forms massive habits but sometimes can be found as prismatic, needle-like crystals and in botryoidal (globular) forms. It frequently forms the matrix that other more aesthetic minerals and crystals are found on.

2020年2月28日 · Massive specimens of goethite are relatively common with a reniform, botryoidal or stalactitic habit. These specimens are made of numerous acicular crystals and were found in Cornwall and the states of Michigan, Wisconsin and Minnesota in the USA. Individual crystals are rare, the best ones are found in pegmatites from Colorado.

Goethite. Comments: Stellate crystalline aggregates of acicular goethite crystals. Location: Pribram, Bohemia, Czech Republic. Scale: Not Given. © Lou Perloff / Photo Atlas of Minerals

Goethite was the dominant iron ore typically occurring massive, as botryoidal masses, or as stalactites. Goethite is also well-known as pseudomorphs after pyrite crystals, which have been collected from Llantrisant eastwards along the outcrop of Carboniferous Limestone through to Blaengwynlais and Machen.