73225 (4) Impact Melt Breccia
Collection:
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Fact sheet

73225 (4) Impact Melt Breccia

73225 is a light grey breccia that is equant. It is tough, crystalline, homogeneous, and originally described as a meta-polymict breccia. It contains some large plagioclase feldspar crystals and is most likely to be an impact melt breccia; possibly a granoblastic impactite. A thin vein of black glass penetrates the rock. 73225 was picked from a regolith sample collected from the upper part of a trench wall. It has never been subdivided or allocated. Our thin section is thick so birefringence colours are anomalous.

The sample weighed 3.66 grams before analysis and has not been dated.

Further details of this and other Apollo samples are here: http://curator.jsc.nasa.gov/lunar/
 

About this collection

Apollo 17, the final manned landing mission, had two objectives: to obtain samples of ancient rocks from the lunar highlands and to look for evidence of younger volcanic activity on the valley floor.

This small Collection contains material deriving from both periods, including igneous rocks around 4.3 billion years old from the lunar highlands as well as younger volcanic samples dating from about 3.6 billion years ago.

Apollo 17 was launched on 7 December 1972.

Sample details

Collection: Apollo 17
Type
metamorphic
Rock-forming mineral
pyroxene
plagioclase
feldspar
glass
Accessory minerals
troilite
metallic iron
ilmenite
Category guide  
Category Guide
Title
Refers to any word or phrase that appears in the individual rock names. Names are generally descriptive; they allow users to search for broad terms like ‘granite’ as well as more specific names such as ‘breccia’. However, the adjacent descriptions of the specimens captures a wider range of general words and phrases and is a more powerful search tool.
Description
Refers to any word or phrase that appears anywhere in the descriptions of the specimens
Accessory minerals
Minerals that occur in very low abundance in a rock. They are usually not visible with the naked eye and contribute perhapssver, they often dominate the rare elements such as platinum group metals.
Rock-forming minerals
Minerals that make up the bulk of all rock samples and are also the ones used in rock classi?cation.
Timescale
Selecting one or more period, for example 'Jurassic'.
Theme
A term used to group together related samples that are not already gathered into a single Collection. For instance, there is a ‘SW England granites’ theme that includes such rock types as granite, hydrothermal breccia, skarn and vein samples.
Category
A general term used to label a rock sample. It is a useful way of grouping similar samples throughout a collection. Category names are often, but not exclusively, common rock names (e.g. granite, basalt, dolerite, gabbro, greisen, skarn, gneiss, amphibolite, limestone, sandstone).
Owner
The owner of the sample that appears in the collection. For example, NASA owns all the samples that appear in the Moon Rocks collection
We would like to thank the following for the use of this sample: