Suppose you did not have any indicator available, how else would you be able to identify the end point of the titration?

Indicator is used to detect the end point of a titration by visual change of color. Indicators can be acid base indicator, precipitation titration indicator and redox indicators.

An acid base indicator shows different colors in acidic and basic media. So, in the absence of an acid base indicator the equivalence point can be determined by monitoring the changes in pH as the acid-base titration proceeds.

A precipitation indicator forms colored precipitate at the end point. In the absence of such indicators, the point where the formation of the precipitate just starts to take place is taken as the end point.

In a redox titration, the indicator used shows different colors in acidic and basic media. In the absence of redox indicator, usually one of the solution being titrated acts as a self indicator, like permanganate solution. So, there will not be any need to add an external indicator in such cases.

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).