[analyzer]

How can I Chemical Analyze carbon in order to be sure that my sample is pure carbon ?

I'll be really thankful if anyone can help...

[sjb]

What sort of level of impurities do you anticipate?

S

[Arkcon]

What sort of level of impurities do you anticipate?

S

Also, what types of impurities do you expect?  What is the carbon for, and what impact on the final application will impurities have?

What instruments do you have access to?

These are all questions an analytical chemist should ask, before the task put before them is accepted.  No one should ever expect they can drop a rock on your desk and say, "You're the chemist, you figure it out."  Being able to build an analytical plan around these sorts of question is part of your job as an analytical chemist.

[analyzer]

Thank you for your kind replies.

I am not a chemist, (Student of Gemology) & unfortunately I don't have access to any significant device.

I am suspicious about a piece of rock to be diamond of an industrial quality. The specific gravity & the general characteristics such as its inclusions & hardness do match, nanodiamond crystals within the crystal is totally observable under 40x magnification.

it weighs about 1 gram & is from a natural source (Alluvial).

But some of the optical properties show some variations! The crystal must be of a cubic type, but it doesn't really behave that way...

I am willing to be sure if this crystal really is diamond or not...

Is there any way to determine the chemical formula of this crystal using simple experiments just to get some idea of what it could be?

Thanks in advance.

[xoggyux]

is it hard? e.g can you scratch glass with it?

[analyzer]

Yes the hardness is high ,

It is between 9 & 10 on Mohs Scale, The Specific Gravity is between 3.5 to 3.6, & the color is White.

Characteristic Inclusions of diamonds are present & they are likely to indicate a cubic host crystal but the puzzling point is its Refractive Index! The refractive index appears as 1.61 - 1.62 which is significantly lower than that of diamond.

The refractive index & the specific gravity are likely to indicate topaz but the hardness, internal characteristics & its luster indicate that of a diamond.

[Borek]

Is there any way to determine the chemical formula of this crystal using simple experiments just to get some idea of what it could be?

Doubtful.

[Arkcon]

Thank you for your kind replies.

I am not a chemist, (Student of Gemology) & unfortunately I don't have access to any significant device.

OK.  So you're looking from some sort of bench top, wet chemistry assay for carbon.  Tricky.  Try burning it.

I am suspicious about a piece of rock to be diamond of an industrial quality. The specific gravity & the general characteristics such as its inclusions & hardness do match, nanodiamond crystals within the crystal is totally observable under 40x magnification.

The terms "nanodiamod" and "observable under 40 X" aren't making sense to me.  You have a rock, from a river bed, that is part diamond, and part not, which matches some physical tests, but not some others, but is a single crystal throughout?  I'm not following.

it weighs about 1 gram & is from a natural source (Alluvial).

But some of the optical properties show some variations! The crystal must be of a cubic type, but it doesn't really behave that way...

I am willing to be sure if this crystal really is diamond or not...

Is there any way to determine the chemical formula of this crystal using simple experiments just to get some idea of what it could be?

Thanks in advance.

Try instead to prove that it's topaz.  If you fail, then you can believe it is diamond.  I don't know of a simple chemical test for topaz either, 'tho.

[analyzer]

Yes it is a single crystal.
Under magnification, using a microscope I have found very tiny crystals of diamond with octahedral habit within the crystal.

The internal inclusions are quite strange for me    which made me think of other techniques for identifying the stone, such as chemical analysis.

 

[xoggyux]

could it be one of those artificial diamonds?

[analyzer]

could it be one of those artificial diamonds?

I don't think so... Infact I bought it during one of my fieldtrips.