McColl & Warren state that: "The ruby occurs either as well-formed hexagonal tabular crystals up to 5 cm in diameter and 1 cm thick, .... or as roughly ovoid masses up to 12 cm long, which are single crystals without external form. The smaller discrete crystals generally show the best ruby colour. The larger pieces are hexagonally zoned in shades of red ..... and are generally more opaque. The largest single fragments recovered weigh about half a kilogram. Very little fully transparent ruby has been found: the small to medium size crystals are commonly translucent .... , but in the larger pieces are grossly clouded with fine gas filled fissures roughly following the rhombohedral parting directions..... Scarce mica flakes (phlogopite?), and accessory rounded subhedral zircon, are present as inclusions in the peripheral zones of some crystals".
Mistral Ruby Mine, Spriggs Creek Bore, Ambalindum Station, Harts Range, Central Desert Region, Northern Territory, Australia