Formed well below the earths surface hundreds of millions of years ago as molten rock from the mantle tried to force its way to the surface (But did not succeed) the rock that is now the mountain formed a huge bubble underground and then cooled slowly, forming granite with its large crystal structure and unusual weathering characteristics (it tends to peel away like an onion which accounts for the rounding of the cliffs and boulders). The most common minerals in this type of rock that are easy to see are quartz (White and hard), felspar (often cream, light pink or brown) and mica (the black or silver shiny bits).
The early miners searched but found no gold on the mountain as gold rarely forms in granite (and then mostly in intrusive dykes that occur later than the host rock formation). The heat and pressure of the molten granite forcing its way into the overlying sedimentary rocks is, however, believed to be one of the causes of the mineralization in the Metamorphic geology surrounding the granite mass. The areas in the Buckland just to the East of Mount Buffalo were rich gold bearing areas.
VALUABLE MINERALS ASSOCIATED WITH GRANITE
Tin ore (most commonly in its oxide cassiterite) is one of the common valuable minerals found in Granites. the Beechworth Granites (Nearby) being a major producer of this metal for the state. Luckily (or mining may have damaged the mountain top) there were no valuable minerals found on our mountain. Other minerals of gems associated with granite type rocks (Many found at Beechworth) include Amythyst, Citrine and other Quartz crystals, Tourmaline, Topaz. Molybdenite (used to harden steel and as a dry lubricant) and a range of other interesting (and sometimes radioactive) minerals.
Granite is mildly radio active and has a range of uranium family minerals in tiny ammounts spread throughout. Not at dangerous levels however. Your luminous watch has higher radiation levels.
EROSION and TIME
Time wind, water and ice have eroded away the overlying rock leaving behind the
mountain's amazing granite formations. The sedimentary rocks that
originally covered the area (and some of the metamorphic rocks of the
contact zones) can still be seen at places on the road to the mountain
PEGMATITES and DYKES
Pegmatites and dykes will be found in the granites of mount Buffalo by
the observant person (although not gem crystal rich as are the pegmatites
of the Beechworth Granites).
Inclusions of the original overlying rock that became caught in the molten rock (called Xenoliths) are also interesting and quite
common. These are the rounded edge darker and often micro crystaline patches that can be seen on the surface in places. Easy to see on the horn walking track.
The browns and greys and other colours that are common when you look at the boulders and pinnacles are actually lichens and mosses. The true colour of the granite can be seen below some of the lookouts (Where chemicals from the metal and concrete have killed the living plants leaving the natural rock colour) or where the rock has brocken away recently.
LANDSLIDES and CLIFF COLLAPSE
Granite rock weathers much slower than many other types and also the rounded surfaces tend to provide stability so rock falls and the like occur rarely. It is all a slow process weathering in the granite country. There is a good example of a large landslide (about the year 1999) along the road to Cresta valley. Pass the Cathedral Car park and when continuing on look back at the southern slopes of the Castle Feature and you will see a HUGE boulder half way down a massive scree slope. This boulder has Little Lichen discolorations as it ended upside down and now sits a different colour to its new fellows. Driving around the base of Mount Buffalo on the Buckland, Ovens or Buffalo River roads will also reward the observant with land slips ans slides. Most of these are the result of increased erosion of the steep slopes after the recent bushfires.
Caves in granite are quite rare (Limestone caves being the most common type) but Buffalo has a number. Notably the underground river cave (see adventure activities for our wild cave tours) and two other smaller caves (one Vertical). By definition a cave must have areas of total darkness so the many cracks and crevices and overhangs are just that and are not true caves.