COMPOSITION

The composition tool is useful when studying minerals at their molecular level. The tool allows you to search/calculate molecular weights, generate empirical formulae and perform compositional analysis on any formulae of interest. Of 'the 5 Resources' tools available, composition is the only tool that has practical use outside the scope of this App.

The Composition tool has four functions which are Search weight, Calculate weight, Empirical formula and Get composition with selectable exclusory buttons.

Search Weight

Selecting this option allows you to search the database for the weight(s) matching inputted figures on the sole available text input area. This is as simple as…

• Make sure the 'Search Weight' function is selected.

• Input the weight figure on the text input area. 

• Tap the round floating button at the lower right of the screen to get your results.

The search weight function is very selective of what data it allows to be executed so it will attempt to verify every input you’re trying to give it. Example, if you attempt to pass anything non numeric (such as letters) will result in nothing getting processed. Search weight will also inform you of any failures during processing and how to overcome them via a small text popup at the base of the tool.

The Search weight also accepts thousand grouping by commas ',' and spaces. Decimal separation is to be done by a period/dot '.' hence formatted numbers have to follow the format ##,###.dddd or ## ###.dddd. Comma decimal separators are not supported and will lead to errors on your results when used.

After a successful search and results are available, you can visit the mineral matching your search criteria by tapping it on the results list. This will lead to a new 'Mineral details' interface for that mineral.

Accepted formula standards

With the exception of the 'Search weight' function above, all other functions accept chemical formulae for processing. For this reason, there are standards that Smart mineralogist enforces to make sure the formulae provided are accurate. The following guidelines highlight how the composition tool evaluates inputted formulae. Following them will reward you with error free processing for your formulae.

1. The tool is case sensitive and expects valid chemical element symbols to be used in your formulae. Example; mg2sio4 will not be processed. To properly calculate this formula input Mg2SiO4. 

2. If a formula is all numeric or has characters outside the English alphabet, then it will not be processed.

3. Unicode super and subscripts are not recommended due to different ways Android manufactures have implemented them (or not at all) on their devices. For example, inputting Fe²⁺Al₆(PO₄)₄(OH)₈ by copying and pasting the formula might produce erroneous results or outright fail due to the presence of both the super and subscripts. To input the formula correctly, type or paste the formula as-is without any super/subscripts, Example Fe2+Al6(PO4)4(OH)8. If your device correctly supports the full super and subscripts Unicode set, then feel free to use them without error. You can find out if this is so by trying to search for formulae with these special Unicode symbols. If the search results display them correctly, then your device is good to go.

4. Commas, positive '+' / negative '-' signs, vacant '☐' and bullet operators '·' (conveniently available on the English keyboard from Android 4.0 and onwards) are supported.

5. Rare earth elements are allowed using the symbol 'REE' (in block letters).

6. Failure occurs if invalid elements are present in the formulae. Example, the Letter 'J' or 'Q' does not exist on any element of the Periodic table. Furthermore, it’s not possible for a chemical element to start with an under case letter as all major elements start with block letters.

7. Formulae with discontinuity such as SiO2∙n(CH4,C2H6,C3H8,C4H10); [n; max = 3/17] are not supported despite being valid chemical formulae. Formulae should not have any space between their elements. 

8. Failure will occur when you have mismatching number of brackets on your formulae, example [(Mg,Ca)2(SiO4]. While on the same subject, only three bracket types, curly { }, square [ ], and parenthesis ( ) are supported. Angle < > brackets are not allowed.

9. Synthetic elements (elements with Atomic number greater than 98) are not supported.

Calculate Weight

Selecting this option allows you to calculate the molecular weight of ANY formula provided it follows the standards for writing a chemical formula described above. Meaning just like the filters placed on Search weight, Calculate weight has its own filters to verify if what you’re inputting concedes to the tool’s chemical formula standards. To calculate your formula,

• Make sure the 'Calculate Weight' function is selected.

• Input your chemical formula on the text input area.

• Tap the round floating button at the lower right of the screen to get your results.

If the formula passes, its molecular weight will be calculated. If not, a helpful text pop up will try to guide you on the errors present on the formulae and how to correct them. 

The results of the calculated weight will be displayed in a text below the radio buttons. Tapping the calculated weight value will cause this function to try to match that weight in the database using the 'Search Weight' function before it. This is a good way to search for your formula against known minerals. Example, Inputting Mg2SiO4 and calculate its weight will give you a molecular weight of 140.69. Tapping that figure will search for that molecular weight and give you two results with a perfect match from the database. Those are Forsterite and Ringwoodite. You can browse these minerals from there and see if any of their 5 properties match your sample.

Empirical Formula

Selecting this option allows you to convert ANY formula to its empirical form. Similarly to 'Calculate Weight' before it, this function also has similar standards for inputted formulae before they are processed. It will screen all requirements with the exception of valid chemical symbols. In other words, this function will still calculate your formula to its empirical form even though you inputted non-existing elements. Example, input of (Xi,Mg,Na)4[PO3][Si2O7]3·5-8H2O will still be processed to its empirical form although there is no such element 'Xi' on the Periodic table. To get your empirical formula,

• Make sure the 'Empirical Formula' function is selected.

• Input your chemical formula on the text input area. 

• Tap the round floating button at the lower right of the screen to get your results.

If conversion is successful, the empirical formula will be displayed in a text below the radio buttons.

Get Composition

Selecting this option allows you to get the composition of ANY chemical formulae you input as per standards used by this App. Similarly to 'Calculate weight', this function will also thoroughly screen the formula you are inputting to ensure it conforms to 'accepted formula standards' prescribed above. To generate your composition,

• Make sure the 'Get Composition' function is selected.

• Input your chemical formula to be analyzed on the text input area.

• Tap the round floating button at the lower right of the screen to get your results.

Your formula will be converted to its empirical form before the composition is calculated. If you conversion is successful, you will get… 

• The empirical form of your formula.

• All chemical elements present in the formula sorted by their electronegativity.

• Number of atoms present for each element. 

• Calculated molecular weights.

• Weight percentage of each element in a formula.