Field Equipment and Mineral Test Kit
IFG&MS Presentation on June 13, 2016 – Jim Bosley

Field Equipment You Will Want for Rockhounding
Layered clothing suitable for the weather
Hat and/or umbrella,
Good shoes/boots suitable for walking on rocky and steep hills,
Gloves to protect hands from sharp edges on the rock,
Walking stick to help with balance on steep and rocky surfaces,
 
Drinking water, minimum 2 quarts per person, more if it is a hot day,
Lunch,
First aid kit for minor cuts and scrapes,
 
Maps and guide books to help you get to the collecting site.
Backpack, buckets, and cloth bag to carry the rocks you find
Rock pick/hammer, to dig out and break rocks
Pry bar to pry out rocks,
Sledge hammer and chisel to widen cracks and loosen rocks
Shovel to dig the dirt from around the rock,
Small trowel,
Spray bottle of water to wash off the rock face to help determine if you want the rock,
Wire-screens to separate crystals, quartz or garnets from the dirt or sand, 
 
Vehicle suited to the collection site.  Always go with a friend.
 
Resources:
USGS Quad Maps
BLM and USFS maps
Guide Books
Rockhounding Idaho
Gem Trails of Idaho
Road Side Geology of Idaho
http://geology.isu.edu/Digital_Geology_Idaho/
http://imnh.isu.edu/digitalatlas/geo/fossils/fossils.htm
http://imnh.isu.edu/digitalatlas/geo/gsa/papers/gsac5p17.pdf
http://www.idl.idaho.gov/mining/rockhounding/   
http://www.idahoutdoors.com/rock-hounding-idaho/

Mineral Test Kit Introduction

​There are over 2000 different mineral species composed of chemical elements or compounds. Minerals can be identified by testing their properties and through careful observation. Many rock and mineral specimens are actually composed of a mixture of mineral species.
 
Be sure to test and identify each mineral in a specimen composed of two or more species. Once you have tested a mineral specimen you can identify it by comparing your test results with the mineral characteristics as given in a good rock and mineral field guide.
FIELD EQUIPMENT You Will Want for Rock and Mineral Identification
FIELD EQUIPMENT​
  • Geology hammer/pick
  • Holster for hammer (optional but very useful;
  • Hand lens (10X)
  • Small field magnet
  • Small acid bottle (10% HCl)
  • Mineral Sample Hardness Kit
  • Hard-covered field notebook
  • Pencil
  • Compass
  • Knife or nail
  • Penny
  • Small triangular metal file
  • Plastic bags for specimens
  • Permanent Marker
​​​CONTENTS OF PURCHASED FIELD KIT
  • ​5/10X Magnifier
  • Ceramic Plate (for streak and hardness test)
  • Glass Plate (for hardness test)
  • Acid Bottle (for fizz test)
  • Magnet (for magnetic test)​
  • This kit supplies the basic tools necessary for rock, mineral, and fossil identification and includes: streak plate, glass plate, hand lens, dropper bottle, magnet, nail, penny, and harness scale. From Amateur Geologist - $9.15
​​MINERAL HARDNESS
​Hardness is the ability to scratch another mineral or material. The Mohs scale of hardness consists of 10 minerals varying in hardness from 1 through 10, with talc (1) the softest and diamond (10) the hardest:
  1. Talc
  2. Gypsum
  3. Calcite
  4. Fluorite
  5. Apatite
  6. Feldspar
  7. Quartz
  8. Topaz
  9. Corundum
  10. Diamond
 The hardness of a mineral specimen can be determined by scratching it against the above minerals. If a specimen scratches calcite (3) but is scratched by fluorite (4), then its hardness is between 3 and 4. You can also use common materials to test hardness if you don’t have samples of the minerals that make up Mohs scale. The hardnesses of some materials in a test kit and some other items are as follows:
  • 2.5 Fingernail
  • 3.5 Copper penny
  • 5.5 Glass plate
  • 5.5 knife blade or nail
  • 6.5 Ceramic plate
  • 6.5 metal file
​THE STREAK OF A MINERAL
​A streak is the color of a mineral in powder form.
It is determined by rubbing a specimen across a ceramic plate. The streak is an important identifying characteristic, especially of metallic minerals. The streak of some minerals is similar to the mineral color in lump form. In other minerals that streak is very different from the mineral color. Minerals with a hardness above 6.5 have a colorless streak because they are too hard to leave a streak on the plate.
Wash your ceramic plate with soap and water as necessary to clean it.
​MAGNETISM
​Magnetism can be strong, weak or non-existent in minerals. Test magnetism with a magnet. The specimen is non-magnetic if it is not at all attracted to a magnet. It is weakly magnetic if it has a slight attraction to a magnet and strongly magnetic if it has a strong attraction to a magnet.
​ACID REACTION
​Some minerals are carbonate compounds that dissolve rapidly in acid, producing bubbles or “fizz.”
Test a specimen for this property by placing a drop or two of dilute hydrochloric acid on it. It will produce tiny bubbles if it is composed of carbonate. Dilute 1 part concentrated hydrochloric acid with 3 parts water to make dilute hydrochloric acid. Vinegar will also work, although not as well with some minerals.
Muriatic Acid can be purchased at your local hardware store. 
NOTE: Vinegar is a weaker acid but can be used in many applications for limestone and calcite.  It will take longer and make fewer bubbles.
​SPECIFIC GRAVITY
​Specific gravity is the weight of a mineral compared to the weight of an equal volume of water.
Determine specific gravity by first weighing a mineral specimen to the nearest 0.1 gram (g) using a sensitive balance. Then measure the water volume the specimen displaces when dropped in a graduated cylinder 1/2 full of water. Record the volume to the nearest milliliter (ml) or fraction of a ml. Since the density of water is 1 gram per milliliter (1 g/ml) at room temperature, specific gravity is calculated by  dividing the mineral weight by the displaced volume.