Mineral Database 4+

Nice looking but inadequate

I was looking for an app that would help speed up the identification of minerals in my thin-section work, which otherwise requires a lot of flipping through pages in standard textbooks to find properties that match an unknown mineral. I saw that the Tasa Mineral Database included optical data in its search form, so decided to give it a try.

The app is good-looking, with lots of nice photos of nice mineral specimens. It offers a very wide range of potentially useful information about a good variety of minerals. Unfortunately, this information is a mile wide and an inch thick. The app falls down when you try to put it to work.

The search feature was my primary interest in the app, but it turned out to be frustratingly inadequate. The search interface is a problem. All fields must be filled by typing in data. For example, in the “Optic type” field, the user must type in “U-n-i-a-x-i-a-l”. There are only three possible choices: Uniaxial, Biaxial, Isotropic. Why couldn’t the field (and other fields that have pre-defined choices) be constructed with a popup list so the user could simply tap the desired choice, rather than having to type in long words (and risk spelling errors on the dinky iPhone screen). It makes searching very laborious, especially when searches turn up no results, requiring the fields to be re-entered.

Some search fields offer no hints, so the user has to simply guess what to type, and hope for the best. For example, “geologic occurrence”: what do you type? To try it, I entered “skarn” and got a list of minerals, which didn’t include calcite! Obviously the database is very hit-and-miss. Same for “diagnostic properties”: there is no hint button for this search field, so what do you enter?

Interface inconsistencies are another issue. Each image in the photomicrograph gallery has a (i) button to tap for more information. In some photos, the info screen gives useful information about the specimen. In other cases, there is none. For example, in the numerous photomicrographs of quartz, several different and distinctive forms are illustrated, but pressing the info button simply returns “Photo by Peter Crowley”. This is great for Peter Crowley, but tells the user nothing about the specimen: what exactly are we looking at? The photos are uncaptioned, so again we’re left guessing.

The animated crystal shape graphic only rotates on a single axis, limiting its use. For example, it would nice to be able to look at a crystal from different angles to get an idea of how it might look in a random thin-section cut. The crystal structure models all rotate in three dimensions, but not the crystal shapes.

The app is ill-suited for thin-section work: there is no search field for relief, or for sign of elongation, though some (by no means all) “optical comment” fields mention relief (the calcite description doesn’t, which is an oversight, because variable relief on stage rotation is a distinctive characteristic of calcite). There is no—or at least no consistent— data on pleochroism; it is occasionally mentioned in “optical comment” (though surprisingly not for biotite, glaucophane or ferrohornblende, three of many minerals that have strong and very distinctive pleochroism). Typing “pleochroism” into any of the likely search fields returns no results.

Other information is of limited value (biotite: soluble in hot sulfuric acid), yet another example of how the app tries too hard to cover all the bases, but spreads itself too thinly and fails to satisfy.

I spent the $14 so I’ll probably keep the app to look at or show other people the nice photos, or to quickly look up chemical formulas, crystal systems, etc., but I’ll have to stick with the textbooks to do any practical mineral identifications.