I’ve posted some wonderful new zircon crystals in this Pakistan Red Zircon Update (click here).
These are from a large new find of red zircons from the Astor Valley, in Pakistan. A locality that has somewhat sporadically produced small amounts of fine material in recent years, this find produced a large number of pieces. However, from all I have seen, fine zircons are few. There are two key reasons for this. First, the zircons are enclosed within solid rock with other hard constituent minerals, such that many zircons were broken when they were collected. Second, and a much more prevalent issue, the zircon crystals seem to have formed more or less contemporaneously with most of the other minerals in the deposit – feldspar, biotite mica, and pyroxene – and as a result, most of the zircon crystals are not fully developed. Instead, most zircon crystal growth was interrupted by the growth of these other minerals, and therefore most zircons are simply incomplete, or malformed. And yet, among the well-over 1000 pieces I went through, there were some super crystals. The colour ranges from hues of wine-red to intense, vivid deep red, with some occasional gradation to much lighter hues, almost colourless.

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – 3.0 cm crystal

 Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – 2.0 cm crystal

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – field of view 2.0 cm

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – field of view 2.0 cm

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – field of view 3.0 cm

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – 6.2 cm

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – 5.5 cm

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – 4.8 cm

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – field of view 1.7 cm

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – field of view 2.0 cm

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – 3.1 cm

Note the interesting colour-zoning/gradation in this next one – it is almost colourless at the termination.

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – 1.3 cm crystal

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – 2.7 cm

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – crystals to 0.9 cm

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – 0.7 cm crystal

These zircon crystals fluoresce yellow under short-wave ultraviolet light.

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – 3.0 cm crystal
Photographed in short-wave ultraviolet light

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – 2.0 cm crystal
Photographed in short-wave ultraviolet light

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – field of view 3.5 cm
Photographed in short-wave ultraviolet light

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – field of view 2.5 cm
Photographed in short-wave ultraviolet light

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – 4.8 cm
Photographed in short-wave ultraviolet light

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – field of view 3.5 cm
Photographed in short-wave ultraviolet light

Zircon, Astor Valley, Gilgit-Baltistan, Pakistan – field of view 2.5 cm
Photographed in short-wave ultraviolet light