Welcome to Las Vegas!
Although you are technically in Paradise, Nevada
Several stars along the strip near Bally's
The Las Vegas Walk of Fame is a collection of over 100 themed stars that honor those who have helped bring Las Vegas to the world stage. They consits of Red Indian polished granite and are situated over several blocks along the Las Vegas Strip. This type of stone comes from India, specifically from two regions called Karnataka (in the south) and Rajasthan (in the north).
The stones are 1.6 to 1.8 billion years old and were formed primarily through the partial melting of pre-existing continental crust during collisional tectonic events, where older metamorphic rocks were remelted and intruded as granite magma. Due to melt rising from the subducting oceanic crust, the Bundelkhand Craton (craton -> meaning old, continental crust made up of mostly hard rock), began to partially split apart which allowed some of that magma to intrude into a newly formed basin. This then hardened into what is known as granite across modern day central and northwestern India.
Fast forward to the present day, the stars that make up the walk of fame in downtown Las Vegas are water-blasted into three-foot-square chunks of Red Indian polished granite (which formed as described above). Each granite blocks weigh 180 pounds, are two inches thick and cost about $30,000 each. There are over 100 stars in Las Vegas, and each of them hold clues to the geologic past of India.
What makes this rock so red is that it has an abundance of a certain chemical compound called iron-oxide, or more commonly and naturally found within the mineral hematite (pronounced he-ma-tite). Hematite is a not-so common mineral in granite, but it only this abundant when high amounts of it exist within the liquid magma. Below is a chart of other common minerals that can be found in granites.
Granitic Textures
The cooling rate of the liquid magma will determine the size at which crystals can form. The phrase "granitic textures" in the sense of granitic rocks describes the crystal sizes, and not the what they physically feel like to the touch. A slowly cooling magma can produce large crystals. Granites that cool rapidly will form aphanitic texture which lacks a visible crystals to the naked eye (although they can be seen under a microscope). However, rocks that contain a glassy texture were quenched (or cooled within minutes) and lack no crystal structure even on a microscopic scale. These were cooled extremely rapidly, likely due to magma (or lava) coming in contact with water (as seen in Hawaii). By definition, glass has no minerals because there is no overall repeating mineral crystal strucutre.
Those are just some examples of granitic textures. Below is an image of some other textures, each vary by the way the magma cooled.
Works Cited
https://www.ktnv.com/news/investigations/las-vegas-walk-of-fame-tributes-to-reappear-after-mysterious-hiatus
https://www.tripadvisor.com/Attraction_Review-g45963-d8611747-Reviews-Las_Vegas_Walk_of_Stars-Las_Vegas_Nevada.html
https://stonegalleria.in/granite-quarries-in-india-a-state-wise-exploration-of-mines-and-production/
https://www.tandfonline.com/doi/full/10.1080/00206814.2024.2400694?af=R
https://graniteandpaving.com/product/india-red-granite-flat-markers-12x24x4/
https://geologycafe.com/class/chapter3.html
https://www.geologyin.com/2014/07/texture-of-igneous-rocks.html
TO LOG A FIND ON THIS CACHE YOU MUST ANSWER ALL OF THE QUESTIONS BELOW. You can contact me through the geocaching message center or email to submit your answers. Any incorrect answers may result in a clarification response.
1. "Las Vegas" on the first line of your message AND list all geocaching names of your party so I can match your answers to them. If you all want to learn something, I would prefer each cacher send me individual emails in the spirit of earthcaching.
2. Take a photo of you (or you signature item if you don't want your face to be shown) with the "Los Cachorros de Juan Villarreal" star at the above coordinates.This photo MUST be uploaded to your "found it" log. Please do not send any photos through the message center as Groundspeak compresses images. Each log MUST have a unique and different photo. No two logs may contain the same photo.
3. Describe the (a) physical textures, (b) range of colors and (c) relative sizes of the mineral grains of your star. And (d) how does this compare to adjacent stars?
4. Using the mineral chart above, what is the most dominate mineral in your star? How can you tell?
5. Using the granitic textures chart above, what type of texture does this rock have?
6. Based on your answer in 5, did the rock cool fast (or slow). How can you tell?