Mini Me Geology Blog » igneous rock

Diamonds are more than a girl’s best friend, they are April’s birthstone too!

tracyb — Thu, 07 Apr 2011 15:48:50 +0000

Did you know that pencil lead and diamonds are made of the same thing? It is hard to believe but they are both made of carbon! The carbon forms in different crystal types or shapes, which is why they are different. Diamond is the hardest mineral, being a 10 on the Mohs hardness scale. Diamonds are found in igneous rocks called Kimberlites, which are formed deep underground (between 90 and 280 miles below the surface of the Earth). This photo shows cores of kimberlite rock from a drilling event. Rock cores are stored in core boxes for examination.

The largest diamond ever found is over 7,000 carats which is about the size of your two fists put together. Because of their beauty and strength, diamonds are used for a wide variety of products from jewelry to industrial cutting blades. The photo at top left shows a group of different sized diamonds which have been cut and faceted.

Do you know Volcanic Breccia?

tracyb — Mon, 07 Feb 2011 14:54:38 +0000

Volcanic Breccia is a unique extrusive igneous rock that is has large, angular fragments stuck in a fine-grained rock background. This rock forms during an eruption when when rock fragments are plucked off of the inside wall of the volcano and are stuck in the lava, or when rock fragments are picked up from the ground by flowing lava. The rocks fragments become stuck in the lava and become part of the larger rock.

Visit Mini Me Geology where you can find volcanic breccia as an individual sample as well as a part of our My Rockin Collection Deluxe Igneous Rock Kit, our Junior Igneous Rock kit, and in our Igneous Investigation Rock Detectives kit.

Volcanic Breccia Trivia!

Since the types of rocks in and around a volcano can vary, the minerals that are contained in volcanic breccia can be different between samples.
Conglomerate rocks are often confused with volcanic breccia. However, volcanic breccia has angular rock fragments and conglomerate has round rock fragments.

Our Most Popular Ask-a-Geologist Question…..EVER!

tracyb — Mon, 22 Jun 2009 18:27:47 +0000

This has to be the most-asked question we receive here at Mini Me Geology. There must be a middle school or high school text book or worksheet out there that is used by many schools in the country. I think the question is worded a little funny, but here is the question and answer. For all of you teachers out there, take a look at this question….I think the weird wording is throwing the students off because I have been asked this question (worded exactly the same) dozens of times!

Question: What are the hollow ball-like objects, such as quartz, which are found in sedimentary rocks?

Answer: By “hollow ball-like objects” I believe you are thinking of geodes. Geodes are round in shape and hollow in the center. Geodes are usually filled with crystals such as quartz and amethyst. This photo shows several unopened geodes and some that have been cracked open with a rock hammer. The open geodes show the layers of quartz on the inside. Geodes form when an opening (hole) is present in a sedimentary or sometimes igneous rock. Silica-rich waters fill the opening and begin depositing agate and quartz crystals into the opening.

To purchase your own geodes, visit the Unique Rocks & Minerals section at www.MiniMeGeology.com. You will receive a set of 4 large (2″+) geodes that you can crack yourself. Full instructions for both cracking the geodes and doing it safely are provided.

What are some household items made out of igneous rock?

tracyb — Thu, 12 Mar 2009 17:22:52 +0000

Many building materials are made of granite such as counter tops in homes. Pumice, shown in the photo on the left, is also used in products such pumice stones which are used to smooth rough feet and in Lava Soap which is used to remove grease from hands.