Yttrialite-(Y)

yttrialite-(Y)

gadolinite

thalenite-(Y)

thortveitite

Images

Formula: Y2S2O7
Sorosilicate, usually metamict, thortveitite group
Specific gravity: 4.31 to 4.56
Hardness: 5½ to 6½
Streak: Greenish white or white
Colour: Orange-yellow (when altered), olive-green, greenish and brownish black, blackish or reddish brown
Solubility: Forms a gel in hot hydrochloric acid
Environments

Pegmatites

Yttrialite-(Y) is a late-stage yttrium-bearing mineral in some rare-earth-bearing pegmatites, associated with gadolinite-(Y), tengerite-(Y), thalénite-(Y), thortveitite, britholite-(Y), fergusonite, xenotime, allanite, microcline, albite, quartz, biotite, zircon, magnetite, spessartine and fluorite (HOM, Webmin, Dana).

Localities

The type locality is Baringer Hill, Bluffton, Llano county, Texas, USA.

At the Rode Ranch pegmatite, Llano county, Texas, USA, yttrialite-(Y) occurs with thin laminations of tengerite-(Y) (AM 58.545).

Alteration

Yttrialite-(Y) alters to Y-carbonates, tengerite-(Y) and others (Dana).

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