Zircon

Physical Properties
Chemical formula ZrSiO4
Class Nesosilicate
Isolated tetrahedra
Crystal system Tetragonal
Habit Square prisms
Pyramids
Rounded grains are also common
Color Brown to green
Gray
Red
Colorless
Hardness 7.5
Specific gravity 4.68
Cleavage Poor (100), poor {101}
Fracture Conchoidal
Luster Adamantine
Transparency Translucent to transparent
Streak Colorless to white
Optical Properties
PPL Colorless to pale yellow or brown
May be weakly pleochroic
High relief
May display pleochroic decay halo
XPL High birefringence
High relief
May display decay halo
δ 0.06
after Perkins, 349

Zircon in Hand Sample

It’s really hard to find zircons in hand sample that are large enough to see, let alone to be worth gigapanning. So there are no zircon hand sample images for you. Sorry about that.

Here’s an explorable scanning electron micrograph of zircon, though.

Zircon in Thin Section

Thin Section GigaPans

Zircon in biotite gneiss, plane polars (see snapshots)

Zircon in biotite gneiss, crossed polars (see snapshots)

Now see if you can find the zircons in this biotite granite, shown here in plane polars and here in crossed polars.

The zircon grain shown here features a decay halo.

Zircon in biotite, PPL
Zircon in biotite, XPL

Further Reading

Zircon at webmineral.com

Zircon at mindat.org