SAKALAMA sandstones, mineralogy, geology of the Ilakaka sapphire


SAKALAMA SAPPHIRE

( Ilakaka Area)



Sakalama is located in Bara country. This tribe from southern
center of Madagascar was at the origin of many thefts, raids
between its members who disputed the domination of the area
within the previous centuries.
Their dominating inclinations pushed them to attack the close
tribes, in particular those located in the south of their area.
The nature drove Bara becoming pastors and also solids
armed walkers.


Thus, when a young man becomes adult, the habit requires that
he mark this passage by the theft of zebus so that he proves
his courage. Thus he will be able to marry.

The theft of ox is a current activity for the Bara who are
famous for that.
It should be said that they are not alone to practice it, because
this work can be regarded as a national sport.




The robbers of zebus are called malaso. Following the precious stones discovery on their
territory, a part of them was naturally transformed into brigands, attacking those who can have
an interest for them; miners, local middlemen, foreign customers are exposed there.






	The Isalo sandstone
	composes the essence of
	the landscape of this area.


	The first deposits consist of
	conglomerates, gravels and
	sands cemented more or less
	loosely by clays; if the distribution
	of sands and gravels is about
regular, it is not the same thing about the conglomeratic formations always very restricted.

These deposits consist of materials of crystalline schists, granites, volcanic rocks varying
with the basins, the age and distribution.

One finds there elements of rocks and minerals: quartz, feldspars, micas, zircons, tourmalines,
ilmenites, magnetite, monazite, rutile, chrysoberyls, corundum.

The elements of rocks are of very variable size and sometimes of strong dimensions but,
generally, it do not exceed 5 or 6 cm. The types with large elements appear localized
close to the littoral zones; on the other hand the gravels and the sands are almost regularly
distributed in the content of the basins.




	This sapphire of natural color,
	therefore untreated was found
	in alluvium in the sandstones.
	This is why it does not have
	any more its original shape.


	Bezabo mount (1066 meters)





The conglomeratic zones in most
of the cases, correspond much more
with falls than with alluvia, however
the elements of these rocks are
rolled at the same time more and
more, increasingly fine and better
cemented towards the top of
the deposits, however without
classification by size there.

The lithological variations of these sediments are in connection with the substratum. Very
strong proportion of biotite and corundum and mica schist elements at the same time on or
close to the substratum with talcschists; elements of quartz and quarzites largely dominant




Currently, this zone is prohibited to the foreigners, it is also the case of all the Ilakaka
area. Foreigners can reside at the edge of the trunk road only, provided that they
are holders of a permit.