This earthcache is on the famous Mackinaw Island. Nearly 1,000,000 people visit this island each year and some of them come soley to geocache/earthcache !
The purpose of this earthcache will be to focus on the PHYSICAL ATTRIBUTE of this crystal's 'LUSTER'.
Your first goal is to wander the beach near GZ (you might get lucky and find the same boulder I did when I placed this cache), and look for a rock with a crystal(s) embedded within the rock. look for slices where the minerals could collect and form crystal.
FTF: turtleman810
LOGGING REQUIREMENTS:
1- Based on the descriptions below, which type of 'luster' do you see in the mineral/crystals that have grown in the crack in your rock?
2- What is the approximate circumference of this rock?
3- What is the length and width of the crystal growth.
4- Submit a pic of yourself with your GPSr if you wish. If at all possible, include a photo of the crystals you found.
Long ago, Lake Algonquin covered all but the center of Mackinac Island. That high point is now 75 feet above the now Lake Huron. This earthcache relates to CRYSTALS that you can find at the listed coordinates.
About the crystals:
How are crystals formed? Crystals can be formed in a variety of ways. Typically when you find crystals within the cracks of a rock, they have orginated as a liquid. Hot water circulates in many places in the Earth's crust. This water carries a rich load of dissolved minerals - just like a 'chemical soup.' The 'soup' deposits minerals as it cools, forming mineral veins in cracks or rock crevices.
Let me illustrate how crystals are formed by showing how you can make a crystal at home. Simply heat up some water and put it in a clear jar. Add sugar to it until the water can't absorbe anymore. Pour that solution into another empty jar without letting any undissolved sugar in it. Tie a string in the middle of a pencil and allow the string to dangle in the solution. Let the jar sit in he sun, allowing the water to evaporate. Soon you will see crystals forming on the string.
Minerals/Mineralogy: There are over 4,000 species of minerals. Of these, prehaps 150 can be called 'common,' and another 50 are 'occasional.' Physical mineralogy focus is on the physical attributes of a mineral. Like: structure, LUSTER, color and hardness. Chemical mineralogy focuses on the chemical composition in order to identify. There are a few minerals which are classified as whole elements like copper, silver and gold. Biomineralogy is the study of how plants and animals stabilize minerals under biological control. It uses techniques from chemical mineralogy to determine such things as growth forms in living plants and amimals as well as things like the orgional mineral content of fossils. Optical mineralogy is a specific focus that applies sources of light as a means to identify minerals.
Geology: Crystals are solid material in which the atoms are arrranged in regular geometrical patterns. The crystals shapes are the external expression of the minerals regular internal structure. Temperature, preasure, chemical conditions and the amount of space available are some of the things that affect their growth.
Luster: This is a term used to classify what crystals looks like in the light. You will need to examine the LIST below and successfully classify this boulder's 'crystals' that can be found in the crack.
- Dull / earthy -- very dull
- Waxy -- like the surface of a candle
- Greasy / oily Pearly -- like a pearl, play of colors, light
- Silky -- has a shiny surface like a piece of silk cloth
- Glassy / vitreous -- looks like glass quartz, many rock forming minerals
- Resinous -- looks like freshly broken shellac, 'diamond-like'
- Sub-metalic -- silvery or metalic luster
- Metalic -- very shiny, like processed metals, highly reflective, opaque