Mineral Identification Lab
Assignment: Identify all the minerals in the tray provided. Fill out Mineral Data Chart.
A mineral is defined as being:
- _________________________
- _________________________
- _________________________
- _________________________
- _________________________
A rock on the other hand, is an aggregate of _____________________ minerals.
The identification and recognition of minerals are based on certain ____________ _____________ which they exhibit. Some of these physical properties are: Luster, Color, Hardness, Streak and Cleavage.
Luster is the way a freshly broken mineral surface reflects ________________. Minerals which look like metal when they reflect light are said to have a __________________ luster. Non-metallic looking minerals may be described using terms such as vitreous (glass-like), resinous, pearly, silky, dull, waxy, greasy, earthy, brilliant, etc.
Color is also determined by examining a fresh mineral surface. Color is only a diagnostic feature in some minerals since it may vary greatly due to slight differences in ________________ _______________ or traces of ______________.
Hardness is a minerals's resistance to being _________________. The degree of a mineral's hardness is measured on a scale of 1 to 10, known as Moh's hardness scale, where 1 is the ____________ and 10 is the _____________. Ten common minerals represent each of the numbers of the scale. It can be determined if a mineral is harder or softer than another substance (such as glass or fingernail) simply by trying to scratch it with the mineral.
Moh's Hardness Scale
- ________
- Gypsum- fingernail
- Calcite- penny (copper)
- Fluorite- nail
- Apatite- glass
- Orthoclase feldspar (K-feldspar)
- ____________
- Topaz
- Corundum
- _____________
Streak is the color of the mineral in its ___________________ form. It can be powdered by rubbing it against a piece of unglazed porcelain known as a streak plate. A small residue of the mineral will wear off on the plate. This test is especially useful for identifying minerals with a ______________ luster.
Cleavage is a mineral's tendency to break along definite plans of _________________ that exist due to the mineral's _____________. Cleavage may exist, but not be obvious. Often, a mineral with cleavage will display it in more than one direction. Cleavage must not be confused with crystal face surfaces which is a natural growth pattern.
Other physical properties include:
specific gravity- how heavy a mineral feels compared to its size
magnetism- a mineral's attraction to a magnet
taste- such as the mineral halite which will taste salty
feel- soapy, greasy, etc.
reaction to hydrochloric acid- (such as calcite) it bubbles with the release of carbon dioxide
odor- such as the earthy smell of kaolinite in high humidity and sulphur smell of sphalerite and pyrite
fluorescence- under UV light some minerals glow with a characteristic color such as calcite.
striations- straight, parallel lines on the mineral's surface which resemble scratches
habit- the characteristic appearance or form of mineral having to do with the manner in which they form. Some common examples of habit are:
- micaceous- composed of small flecks
- massive- having no specific shape, composed of compact microscopic crystals
- crystalline- composed of many interlocking crystals.