Using a Mineral Database for Classification

Background info:

A database stores information in categories called fields. Each of these fields can be utilized as an element in a search of the entire database. If a database is set up properly, it can be used for mineral identification. In this activity, a database will be created and then used to attempt to classify several minerals.

One of the purposes of this activity is to give you practice using a database for a meaningful task - not to teach you how to set up the database. Consult the manual for this.

Software:

A generic program like ClarisWorks or Microsoft Works will do the job quite well. These programs often come bundled with a new computer.

Procedure:

Using the database portion of the program, create a new database with these fields:

• Name
• Color
• Luster
• Acid test
• Streak
• Fracture/Cleavage
• Hardness
• Magnetism
• Crystal
• Specific Gravity
• Fluorescent
• Phosphorescent
• Double Refraction

Into each of these fields must be input information for every mineral that will be identified. Be certain to spell everything correctly! In nature, this would be thousands of minerals. For practical uses in this activity, a much smaller range of information may be used. Your instructor will have selected and obtained a group of minerals to be identified.

In addition, your instructor will provide you with a list of these minerals by name.

Your task will be to locate information on each of these minerals and input the necessary information into your database. Your source of information can be science textbooks, the internet, CD-ROMs, mineral books, and anything else available in your local library.

Once you have located the information and put it into your database, you are ready to attempt to use this database to identify the minerals selected by your instructor.

Termonology:

In order to identify the minerals, you will need to understand the termonology being used for the various mineral tests. Each item (field name in your database) will be briefly explained.

• Name, of course, refers to what a mineral is called. Some minerals have more than one common name. These names might vary depending upon the location where the mineral was found.
• Color is referring to the appearance of the mineral by just looking at it. Some mineral may have a wide range of colors. Color is not the best criteria for identification.
• Luster refers to the way light is reflected from the surface. Luster will usually be described in terms such as - metallic, waxy, glassy, or pearly.
• Acid test refers to whether the mineral fizzes or reacts when a drop of diluted acid is placed on it.
• Streak is the color of the mark left by a mineral as it is rubbed on a piece of unglazed tile. The streak may be a different color than the mineral. Some minerals will not leave a streak. The streak is actually a powered sample of the mineral.
• Fracture/Cleavage refer to the way that a mineral breaks. Fracture might be crumbly or glasslike (conchoidal). Cleavage is smooth fractures in flat planes and will be expressed as a number - indicating how many planes the mineral fractures along. Fibrous or splintery are other fracture options.
• Hardness will be expressed as a number derived from the Moh's Hardness Scale. How to determine the number when testing your minerals is explained in most books on minerals.
• Magnetism refers to whether the mineral is attracted by a magnet. Some samples might themselves be magnetic.
• Crystal refers to the shape of the crystals that make up the mineral.
• Specific Gravity equals the mass of the mineral sample in the air divided by the mass of an equal volume of water. This will be expressed as a number.
• Fluorescent refers as to whether a mineral glows under ultraviolet light.
• Phosphorescent minerals will continue to glow after the ultraviolet light is turned off.
• Double Refraction refers to a situation in which the mineral splits light passing through it into two paths. This causes two images to be seen when looking through the mineral.

Getting started:

It is now time to collect mineral information and to build your mineral database.