Mautia Hill, Kongwa, Kongwa District, Dodoma Region, Tanzania

3mm blue Yoderite

© Maurice de Graaf

RRUFF Project Specimen ID: R050277 Locality: Mautia Hill, Kongwa, Central Province, Tanzania Source: Marcus Origlieri Blue anhedral lathlike grains

© Rruff Project

photo and collection Joachim Esche modified Wild M420 photomacroscope with apozoom and Canon EOS 550D

© Joachim Esche 2016

Thin section view in PPL (plane-polarized light) of yoderite (bright blue... hence, lower polarizer is oriented approximately parallel to X vibration direction) separating kyanite (high-relief, v. pale-colored crystal near center of view) from quartz (low-relief colorless grains scattered throughout section). One foliated mass of talc is visible ...

© Frank K. Mazdab

size 6x6 cm. Dark-bluish to black XX of yoderite in quartz-talc schist. Paul Bongaerts specimen and photograph

© Paul Bongaerts

Picture width is 4mm. Dark blue Yoderite. Depth of field is achieved with CombineZM.

© Elmar Lackner 2007

Aggregate of yoderite crystals in thin section, width of the area c. 7 mm. Yoderite grains with different orientation show a very strong pleochroism in blue and violet shades, in transmitted light with single polarizer. It is intergrown with abundant quartz and greyish flakes of talc.

yellow-brown grain of kyanite, rimmed with purplish-blue yoderite; also with colorless quartz. photo and collection Joachim Esche modified Wild M420 photomacroscope with apozoom and Canon EOS 550D

© Joachim Esche 2016

Mass of Quartz with inclusions of tiny red crystals of Piemontite making it look like red Quartz. The vendor told that this is really a red Mn3+ bearing Epiodote in Quartz but Epidote is not listed for this locality. JSS specimen and photo.

Dark purple/blue anhedral grains to 15mm in a talc quartz schist with relicts of orange kyanite. Ex Richard Barstow collection Jason Evans collection

© J.J. Evans

Yoderite violet-blue crystal Helicon Focus stack. sw. Collection and photo A. Zordan.

© Antonio Zordan

Sony Alpha 7R ii, bellows, Mitutoyo M Plan 10x, aperture, Raynox DCR-250 retro, Stack-Master linear actor, stack shot control. Collection and photo Stephan Wolfsried

© Stephan Wolfsried 1/2017

Purple monoclinic crystal of yoderite in talc. Associated minerals, not in the photograph, include, hematite, kyanite, and quartz. Brent Thorne specimen and photograph.

© Brent Thorne 2012

Same as parent photo, but lower polarizer has been rotated 90° so that it is approximately parallel to the Z vibration direction of the yoderite; hence the change of observed pleochroism color from medium blue to pale green. Same magnification and field of view as parent photo. Sample FKM-69 (thin section). EDIT: original photo replaced with ...

© Frank K. Mazdab

Intergrown yoderite crystal, successfully separated from its exclusive talc/quartz matrix, shows association with the brown kyanite for which locality is known.

Dark blue yoderite crystal on quartz. Former Jaroslav Hyrsl specimen. Rolf Luetcke specimen and photo.

I bought this crystal from a good friend who travels to Tanzania in search of gems and gem crystals, and he personally selected this crystal out of hundreds of pieces specifically for me. Most of the apatites you’ll see from the Kongwa District are a soft blue, silvery-blue or greenish-blue color, but they’re almost always broken and are sold ...

© Brian Kosnar - Mineral Classics

Dark blue yoderite in quartz. Former Jaroslav Hyrsl specimen. Rolf Luetcke specimen and photo.

Dark blue-black crystals and crystal sections of yoderite richly embedded in muscovite schist. Older material, purchased from Richard Barstow in 1980.

© Andrew Hodgson

Dark blue yoderite in talc from Mautia Hill, Kongwa, Dodoma, Tanzania.

© Knut Eldjarn

Dark blue Yoderite in unidentified matrix. Acquired from Frank Raquet on Catawiki on 18 August 2023.

Dark Blu Yoderite. Photo with Canon Eos 600D + Bellows + Rodenstock Rodagon 35 mm 1:4,0 reversed. Photo and collection Giovanni Scapin.

© 2025 Giovanni Scapin