Where is Ruby in Zoisite found?
Ruby (Corundum) in Zoisite
Got a photo? Identify rocks instantly with the Rockby app
Open the appRuby in Zoisite occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Ruby in Zoisite
Tanzania
The primary and most famous source, particularly the Longido mining district near Mount Kilimanjaro. This is where the material was first discovered and named Anyolite (after the Maasai word 'anyoli' meaning 'green').
India
Occurrences have been reported in various states, including Karnataka and Odisha.
Zambia
Some deposits have been found, though less prominent than Tanzanian sources.
Norway
Minor occurrences have been noted.
Austria
Known for some historical occurrences.
Collecting tips
- Geological Context. Look for areas with known metamorphic rock formations, especially those associated with chromium-rich igneous or sedimentary protoliths. Contact zones between ultramafic rocks and aluminum-rich sediments can be promising.
- Visual Identification. Search for rocks exhibiting the characteristic green (zoisite), red (ruby), and black (amphibole) color combination. The ruby crystals are typically opaque and can be quite distinct.
- Hardness Test. While the overall rock will have varying hardness, the ruby component (Mohs 9) will be significantly harder than the zoisite (Mohs 6-7) and amphibole (Mohs 5-6). This can be a useful distinguishing feature if you can isolate a ruby crystal.
- Associated Minerals. Ruby in Zoisite often occurs with other metamorphic minerals such as feldspar, quartz, and various amphiboles.
Quick Check
- Color:
- Green with red and black inclusions
- Luster:
- Vitreous to pearly (zoisite), adamantine to vitreous (ruby)
- Streak:
- White (for zoisite and ruby), greenish-white to gray (for amphibole)
Explore Ruby in Zoisite
Identify rocks anywhere
Free on iOS, Android, and Web. Photo identification, full database, and your personal collection.