This earthcache is located inside The Fountain Hills Botinical Gardens. The parking lot is small but there is plenty of parking on the side of the street. Trail is dirt and uneven in places. Please be careful on the trail. Trail is open during daylight hours only.
HOW IS QUARTZ FORMED?
The two most prevalent materials in the Earth's crust are silicon and oxygen. And quartz is made up of these two abundant materials (i.e., it is essentially silicon dioxide). Quartz is the most basic form of silicates found on Earth.
It makes up 12% of the land's surface and 20% of the Earth's crust. That's a lot of quartz clusters for all of us crystal-lovers. It will be a long time before the Earth runs out of clear quartz crystal.
It gets formed naturally when silica-rich solutions occur in the underground cracks and crevices in the earth's crust. These allow for unlimited expansion of quartz clusters.
Even though quartz was used as a weapon by our ancestors, it has been used in jewelry for the past 4000 years.
You might be wondering how the smooth surfaces of clear quartz crystals are formed. They indicate the equilibrium in the crystal pattern and are an indication that the crystal was allowed to grow without any hindrance.
DIFFERENT TYPES OF QUARTZ
There are two different groups of quartz formations that you need to be aware of. Let's explore them in detail below.
CRYSTALLINE QUARTZ
Crystalline quartz can be found both as frosting sparkling on a rock and as well-formed crystals weighing tonnes. It represents the diversity of quartz crystal formation.
As you might already know, the color of quartz crystals comes due to the impurities found in the rocks or sand around the crystal formation. Let's look at the variety of colors we find in quartz.
- Amethyst - purple (due to Ferric iron and gamma radiation)
- Rose crystal - pink (due to titanium oxide)
- Rock crystal - clear
- Milky quartz - white (due to tiny bubbles in the crystal)
- Smoky quartz - Yellow, brown, black (due to radiation in the rocks)
As you can see, crystalline quartz can be quite diverse depending on the circumstances in which it grew.
*Source https://kalifano.com/blogs/stories-of-kalifano/how-is-quartz-formed-everything-you-need-to-know
Vein Quartz
Quartz is often found in veins that cut through rocks. Although the term "vein" suggests this, the veins of quartz and other minerals are usually not thin tubes, but rather thin sheets. The veins can form under various conditions, and depending on these conditions, may or may not contain quartz crystals.
Even though certain types of quartz veins do never bear any crystals, it sometimes makes sense to follow large quartz veins to look for crystal-bearing fissures: Should a rock that contains old large quartz veins have been folded later due to tectonic forces, the quartz veins represented a disturbance (a discontinuity in the otherwise homogeneous mechanical properties), and alpine-type fissures are likely to open up between the quartz and the host rock.
The simplest type of a quartz vein is the filling of an already present crack in rocks. The crack might form during folding of the rock in mountain-building processes, by shattering during tectonic events, by a decrease in pressure during the uplift of a rock, or because a rock cools down and shrinks. Hot brines that percolate the rocks and originate at greater depths with higher temperatures will precipitate the minerals they carry with them in cracks at lower temperatures and pressures. This process may continue until the crack is completely filled or may stop before, leaving "pockets" in the vein that are sometimes outlined by crystals. Hot brines that enter a crack in the rock from some distant hot source like a granite pluton first cool and precipitate most of their load rather quickly. The result is milky quartz, either massive or made of interlocked milky quartz crystals. Later, when the crystal growth slows down, the crystals may get less milky or even clear. In the majority quartz veins, most of the quartz is precipitated as massive, milky quartz. Well-formed crystals, if found at all, are only a small portion of the vein filling.
*Source http://www.quartzpage.de/gen_occ.html
E-mail me with your answers to the questions
1. Examine the quartz, what colors do you see?
2. Did erosion form this quartz?
3. Looking at the quartz vein do you think it is amethyst, rose crystal, rock crystal, milky quartz, or smoky quartz?
4. (Optional) Take of photo of yourself with the Quartz Vein behind you.