Could this be topaz or quartz? Hardness is morethan a quartz

Question

Answer 1

Not quartz, I believe. Yellow staining may be limonite. Could be topaz, diamond, even beryl. Sillimanite is also harder than some quartz.

Answer 2

A hardness test can better identify it. If a quartz cannot scratch it, then it is most likely waterworn topaz. What is its origin?

Comments

they r from india. Extreme hardness.even corundum cannot scratch them.  The specific gravity is 2.60. All confusing with specific gravity.

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I guess being from India, alluvial diamonds is a possibility, but I would find it odd that you would be finding diamonds in India and not be familiar with their identity. If corundum doesn't scratch them, the only other mineral left is diamond. However, the Specific Gravity you shared is off. So by way of conclusion, I would make one of the following hypotheses:
1) You did not conduct a proper hardness test and it''s lower, and would likely indicate waterworn quartz, feldspar, topaz, corundum, or any transparent alluvial mineral.
2) You did not conduct a proper specific gravity test, and the results are likely higher
3) You have a new undocumented mineral to science with a hardness greater than corundum and lower specific gravity than diamond.

The last suggestion is highly unlikely.