Busovača is the World's far best locality for hyalophane. They were found in the mid of 1950' when the Yugoslavian geologists prospected for optical quartz. The hyalophane occurs in Alpine-type veins in Paleozoic phyllite in Zagradski potok west of Busovača.

Since 2013, when the local community decided to build a water dam exactly on the hyalophane locality, access to the pockets is not possible anymore.

Fine specimens with up to several centimeters long hyalophane crystals are not rare for the locality. The largest crystals here measure to 23 cm and they are all twinned! Non-twinned specimens of hyalophane are therefore quite an exception for the locality. To some extent the twinning of hyalophane resembles that of its brother mineral adularia, but can also be far more complex. The most typical complex twins are fourlings, the combinations of Manebach and Baveno twins, as shown in crystallographic studies by my fellow colleague Dr. Mirjan Žorž. See the articles in Mineralien Welt 2016/3, 2017/3 and 2017/4.

The specimen offered here is dominated by one large single hyalophane crystal with alternating {101} and {103} faces grown on black-brown, partially included, siderite. From one side there is a cluster of smaller intergrown hyalophane crystals. The specimen is in good shape with minor cracks and crevices. It originates form the large find in 2009, from the veins discovered after the drainage of the Zagradski potok. These veins produced the last high quality specimens from this locality.