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Formula: TiB2
Boride of titanium
Crystal System: Hexagonal
Specific gravity: 4.52 calculated for synthetic material
Colour: Black?
Environments
Plutonic igneous environments
Volcanic igneous environments
Jingsuiite is a relatively new mineral, approved in 2018.
Localities
At the type locality, the Luobusha ophiolite, Qusum county, Shannan Prefecture, Tibet, China, jingsuiite,
together with
osbornite-khamrabaevite
solid solution, deltalumite and a potential new mineral, constitute
four inclusions up to 50 μm across in corundum recovered from the
chromitite orebody. In one inclusion, jingsuiite forms a
rounded grain 40 μm across. Associated
osbornite-khamrabaevite
solid solution forms an irregular mass up to 10 μm across, and the potential new phase,
Ti10(Si,P,?)7, forms an incomplete overgrowth up to 20 μm thick around the grain of
jingsuiite.
The preferred scenario is that corundum with entrapped
titanium-silicon-phosphorus-iron
intermetallic melts was precipitated from basaltic magmas during
exhumation following deep subduction. Enrichment of boron in the melt pockets
is attributed to the highly reducing conditions.
Experimental work indicates that minerals enclosed in corundum grains such
as titanium, FeTiSi2 and TiSi2 could have crystallised
from alloy melts at temperatures less than 1300°C
(AM 107.43-53).
At the Rakefet magmatic complex, Mount Carmel, Haifa District, Israel, jingsuiite is a minor but common phase
in melt pockets trapped in the corundum aggregates that occur as xenoliths
in basaltic volcanoes on Mount Carmel. These melt pockets show extensive
textural evidence of immiscibility between metallic
iron-titanium-carbon-silicon melts,
calcium-aluminium-magnesium-silicon-oxygen melts and
titanium-(oxy)nitride melts. The metallic melts commonly form spherules in
the coexisting oxide glass. Most of the observed jingsuiite crystallised from the
iron-titanium-carbon silicide melts
and a smaller proportion from the oxide melts under highly reducing conditions
(AM 105.1609–1621).
Associated minerals include
iron-titanium silicides,
osbornite, khamrabaevite and
calcium-aluminium-magnesium silicate glass
(HOM)
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