About The Collection

Thank you for your interest in the Dynamic Earth collection. This web site was developed by Ryan J. Cooper to showcase the beauty and diversity of the Earth, it's minerals and unique natural features, and the dynamic processes of creation, destruction, and transformation that are uniquely demonstrated through the study of geology. We will use this site to explore the magnificent and awe-inspiring beauty of our planet - and to gain a deeper appreciation for, and understanding of the interlocking processes that work on timescales from the momentary to the millennial. Please explore the gallery to discover how minerals relate by color, size, composition, luster, and crystallography. This site features distinctive, one of a kind specimens collected from all over the world, including igneous, sedimentary, metamorphic and hydrothermal minerals and rocks, with most ranging in size from a few millimeters to about the size of a fist.

How do you describe the size of a mineral or rock specimen?
Here is a guide to the terminology of mineral sizing to help you better understand how the sizes of the specimens compare. These sizes are usually just estimates and you may occasionally see something described as one size up or down from its actual measurement noted below.
  • 1- Micromount: Specimens that are very small, from the size of a grain of sand to about 1-2 millimeters in diameter. Best viewed with a 10X loupe or microscope.
  • 2- Thumbnail: Specimens that would generally fit within a 1 inch/2.5 cm box (these are called "perky boxes" in the industry).
  • 3- Miniature: Specimens larger than one inch, and up to about the size of a golf ball or about 5 centimeters.
  • 4- Small Cabinet: Specimens about the size of a baseball or about 10 centimeters.
  • 5- Medium Cabinet: Specimens about the size of a grapefruit or about 15 centimeters. Anything "Medium to Large Cabinet" may be just called "Cabinet Size" by some dealers.
  • 6- Large Cabinet: Specimens up to about 25 centimeters in length on their longest side.
  • 7- Extra Large Cabinet: Anything larger than about 25 centimeters/10 inches, is considered extra large. Also called "Museum Size" in the industry.
In general, the collection focuses on thumbnails, miniatures, and small cabinet sized pieces.

What is an element?
An element is the most basic unit in mineralogy, and one instance of an element in known as a molecule (or "mole" in chemistry). There are currently 118 known elements which include hydrogen, the building block of stars; helium, the product of hydrogen fusion; carbon, the building block of all life - and many other metals, gases, radioactive elements, rare-earth elements, and halogens as defined on the periodic table of elements. These elements combine into chemical compounds to form minerals. On many specimens in the collection you will see the "composition" field, specifying a formula or combination of elements in varying proportions. For example, Quartz has the general composition SiO2. This means that pure Quartz is a repeating matrix of 1 Silica (Si) and 2 Oxygen (O) molecules. It's not really possible to say the exact formula of a mineral just by looking at it, so the composition usually just describes the composition of the primary identifiable mineral (not the groundmass), and it may be a generalized formula, not the exact formula. In some cases the only difference between two similar minerals is the presence of one or two different elements - but that element will often cause the appearance, color, or shape of the mineral to change. A good example of this is the mineral Tourmaline, which famously comes in nearly every color of the rainbow, depending on whether it has chromium or vanadium (green), lithium (blue), iron (red), cobalt (pink) or other elements in the mix. Minerals may also get their color from electromagnetic charge transfers where two neighboring elements within a molecular structure "trade" electrons in their electron orbital clouds. This collection has samples containing most of the common elements, and many rare elements. To make it easier to understand what the elemental formula is, you might also see common terms like Tectosilicate, Calcium Carbonate, etc. which are phonetic representations of the formulas like you might hear spoken out loud in a chemistry class or geology lecture.

What is Chemistry?
Chemistry is the study of matter and the changes that occur in matter.

What is a mineral?
A mineral is a naturally occurring, inorganic solid with a crystalline structure that is consistent and repeating throughout. But even this description has been revised many times - so classifying a true mineral vs. a mineraloid, or a rock, is not always an exact science. Some objects in this collection are not strictly minerals- for example, obsidian is a form of volcanic glass, and opal is a mineraloid that lacks a definite crystal structure. The collection may also feature fossils, shells, elements, and unique biological organisms like pinecones, eggs, bones, and similar natural artifacts.

What is a crystal?
A crystal refers to a singular, uninterrupted growth of a mineral that is distinct from it's groundmass. These are sometimes called "floaters" if the crystal has no attachment to a matrix. Popular floater crystals include diamonds, tourmalines, sapphires, rubies, emeralds, etc. A crystal's external form is a reflection of it's repeating internal structure - so some crystals may externally appear cubic, trigonal, hexagonal, octagonal, or grow in sheets, depending on the structure of the internal repeating matrix and the atomic bonding characteristics of the mineral. This geometrical form is referred to as the crystal habit.

How are minerals classified?
A mineral is generally described based on several specific characteristics including it's crystal habit, hardness, luster, color, streak, density, and cleavage or fracture. Each of these properties can be used in combination to diagnostically determine what type of mineral it is. In addition to these "diagnostic" properties, minerals are also often described in terms of their overall shape or "growth pattern", the intergrowth or "twinning" of multiple crystals in association with one another, and well as by the optical properties of the crystals.

What is a crystal habit?
Crystal habit refers to the various external shapes of crystals that are known to form. These shapes are generally determined based on the molecular bonds of the constituent elements. As an example the mineral Halite (Salt) has a cubic crystal habit, because the constituent elements (Na) Sodium and (Cl) Chlorine bond in cubic shapes at the molecular level. A video explaining this in more detail can be found here.

What is a growth pattern?
Growth patterns of minerals refer not to the shape of the crystals themselves, but to how masses of the crystals grow together, such as in shapes resembling parallel sheets, radiating sprays, sheaves of wheat, tree branches, etc.

What is a rock?
A rock is a mass or group of the same mineral, or a combination of a specific set of minerals in intergrowth. Rocks include familiar and abundant compounds like basalt, granite, rhyolite, and gabbro, which are agglomerations of small crystals of quartz, olivine, biotite, and other igneous minerals. In this collection, you may see references to a crystal growing on a "matrix", or "groundmass" which generally refers to some kind of rock, or larger base mineral like dolomite, marble, granite, etc.

How are rocks classified?
In general, a rock may be either aphanitic (with microscopic crystals), or phaneritic (with visible mineral crystals). A porphyry is a rock which contains multiple sizes of intergrown crystal, in which the predominant mass may be either aphanitic or phaneritic in texture, with additional, larger, visible phenocrysts (distinct crystals) intermingled in that groundmass. These rock textures are an important diagnostic feature of igneous rocks that form in magma pockets deep inside the earth. But over time these textures are changed by forces of erosion, deposition, heat and pressure. Sedimentary and metaoorphic rocks may require more careful assessment to determine their particular composition. The field of petrology is focused on the study of rocks, as opposed to mineralogy and crystallography which deal more with the study of minerals and crystals respectively.

What is a fossil?
A fossil is a formerly living organism that died, fell on the ground (usually) and was subsequently covered by dirt, sand, water, sap, or a solution of multiple compounds. Over thousands of years, the object is lithified (turned into a rock) and its cellular structure (usually wood, bones or a hard carapace) are replaced by minerals like quartz, opal, pyrite, or other minerals. These fascinating objects retain their original form and shape, but tend to be much harder than the bone or wood object that they were originally, because - after all - they are now rocks! These items can provide a glimpse at what life was like millions of years ago, and show us the form of long extinct organisms like trilobites, orthoceras, dinosaurs, etc. So these are rocks in one sense, minerals in another sense, and bones in another sense.

What is a gem?
A gem is any of the group of minerals, precious metals, and rocks that are used in the jewelry industry as adornments. Gems typically include minerals that are of very high grade, exhibiting characteristics of exceptional color and clarity. Gemologists are individuals who are specially trained to identify gem grade minerals by looking for inclusions, fractures, and other imperfections in gems, and using tools like the Chelsea filter to determine whether a mineral matches a particular color profile. Gemologists also can spot fake or man made minerals based on careful analysis of the refraction or physical properties of the mineral they are examining. Gemologists are employed by jewelers and insurers to appraise and assess materials traded in the jewelry industry.

How are the chemical formulas of minerals determined?
In most cases the chemical formula given on this site is the "official" formula, established by the International Mineralogical Association (IMA) or other national standards bodies. When we add formulas, we try to use the version that appears in Fleishers Glossary of Mineral Specimens by Malcolm E. Back & Joseph A Mandarino, published by The Mineralogical Record Inc., Tucson, Arizona, U.S.A. However, these formulas are not always precise to that specimen. In most casses, the minerology is assumed, because that specimen was known to be mined opr collected in association with a mineral that was previously identified. So the formula given is a best guess based on the similar appearrance and characteristics of the mineral, to one that was previously analyzed. In other cases, the formula for a given specimen was actually determined through powder x-ray diffraction (PXRD). This is an expensive process requiring specialized equipment, and most minerals that are analyzed in this way on the collecting market tend to be small, exceptional, valuable, or rare mineral or rock samples.

What are the standards for this collection?
In the mineral collecting world there are many different "flavors" of collecting, and I am pretty particular about a few points. First - I don't primarily collect "crystals" per-se; the collection focuses on well-defined mineral type specimens showing distinct crystal growth habit and termination on a matrix or groundmass. Some of the specimens are floater crystals, but my preference is always to see minerals in a natural state as they would be found (after some cleaning). But as such - this collection is not so much about pretty, showy jewelry grade minerals, faceted stones or lapidary rock. Many of the minerals in the collection appear rather dull or ordinary until inspected closely, and finding that perfect mineral growth on the matrix is part of the joy of collecting for me. I am also rather particular about how the minerals are cataloged- we try to characterize every specimen by type, mineral group, size, luster, composition, and location of origin, and I try to document any modifications to the mineral like repairs, polishing, or mounting, or special handling precautions needed to safely handle that specimen. If the specimen is known to be radioactive, fragile, etc. that will be noted to ensure safe handling. I also enjoy collecting fossils, sedimentary rocks, shells, pinecones, and other similar relics of our biological world - and you may see those interspresed in the collection.

Why is there information missing on some specimens?
We always provide as much information as we have available. In some cases, the exact locality, species or variety is not known. In any specimen where the locality or variety is noted, this should be interpreted as my "best guess" based on statements of the dealer I purchased it from. I cannot guarantee that every mineral is of the type noted, or from the exact location stated - I am generally going off the word of other dealers, miners, or wholesalers who I trust. If you notice information missing, and believe you can help identify a mineral or locality, please contact me and let me know!

Are minerals safe to own and handle?
Most minerals are relatively safe to handle, if you follow a few precautions. Its important to note that many minerals like arsenates contain compounds that are toxic to humans and pets. So you always want to keep minerals out of the reach of children, and wash your hands after handling them. Its also important that you do not lick, eat, or otherwise ingest minerals, or inhale their dust or oxides in a powered form. Some minerals like borax are extremely soft and may irritate the lungs if accidentally inhaled. Lastly - be cautious of any radioactive minerals. A dedicated collector should be aware of the radioactive potential of their collection, and invest in a geiger counter to ensure they are aware of radiation that may be emanating from certain samples. It's not necessarily unsafe to own these - but its always a wise choice to isolate these from their regular collection and keep them away from places where they might be handled carelessly, or locations where your family typically gathers. Over time, the radiation given off may have deleterious effects on your health. Elements to be aware of in your collection as potential sources of harmful radiation, are those containing thorium, radium, and actinides (the bottom row of the periodic table). We test minerals in the Dynamic Earth Collection for Gamma and Beta radiation using a GQ-320 Geiger Counter, and generally tag minerals as Radioactive if the levels exceed 100CPM at an unshielded distance of 3 cm. We will disclose precise radioactivity levels to buyers if requested.

What are the naming conventions for this catalog?
In mineral collecting and classification - the term "species" or "type" is sometimes used to describe a specific version, color, or form of the mineral, and mineral group describes the family that the mineral belongs to. The naming conventions of this catalog or chosen for convenience, and may not always refer to the exact scientific mineral species name, for example, in some cases, you may observe a "group var. species" type notation, like "Garnet var. Almandine" or "Corundum var. Ruby" when the collection contains multiple similar specimens of one group - or in some cases, a species name only may be used. The convention here is to refer to the minerals in the way that most people know it - and usually put the group before the species. So while its more natual to say "Hessonite garnet" in this catalog it will be listed as Garnet var. Hessonite. This is just to make it easier to see all the quartz, garnet, and other related groupings for which the collection has several variants.

What is a type locality?
If you notice the term "type locality" used in this catalog, that indicates that this mineral was mined or collected form the same (general) location where it was first discovered or described. So you might say these are the "best expression" of that mineral - they are the closest in appearance, form, color, and growth habit, to the form of that mineral that gave it it's name.

What about the healing / spiritual qualities of crystals?
We respect the passion that others may feel about minerals, and how they personally believe that holding a crystal gives them spiritual insights or enhance their abilities to channel healing energies. But we do not actively document or engage in discussion about the healing properties of minerals, or add details on these qualities. We are interested in the minerology, crystallography, and natural forces that create minerals. Just as Astonomy and Astrology are very different ways to observe the sky - mineral collecting and crystal healing are very different concepts - but we think anything that gets you to look at the universe in wonder is a good thing. If you love minerals for spiritual reasons, we encourage your spirit of creativity and wonder toward these treasures, and we also encourage you to get to know some of the scientific qualities that make them so inspirational to us!

A word from our Curator, Ryan J. Cooper
I have been a dedicated collector for most of my life - my family owned a owned a collectibles business which I worked at from a young age. As an adult I pursued a deeper understanding of the intersection of science, museum studies, and private, hobby collecting. I have an Associates degree in Natural Sciences from the Santa Rosa Junior College, where I studied Geology, Astronomy, Meteorology, Anthropology, Resource Management, and related Earth science disciplines. I have spent most of my professional career studying computer science, data and information management, cataloging and e-commerce technologies, and content management systems and strategies. I also earned a professional certification in Data Science from Harvard University Online (HarvardX), which has been a huge contributor to my understanding of how to consume, organize, and analyze large quantities of data, essential skills to manage a substantial onlne catalog such as this! I have been a fan of many collecting hobbies - from baseball cards to comics, rare antiques, old cars, rare maps, and other paper ephemera; but I have found that collecting and documenting minerals provides me the greatest satisfaction and wonderment as I build out the museum collection and find new and exciting pieces to add to the catalog. It is always my intention to purchase only pieces that are legally and ethically sourced, unique, and curiosity-inspiring pieces that tell a story about the Earth, and show how its' dynamic processes can produce objects of the greatest wonder and beauty.

Purchasing & Sourcing Minerals
We do not advertise pricing on the catalog, but if you see a specimen that interests you, or if you are looking for an acquisition agent to help you source a rare and exceptional specimen, please use the contact link in the top menu, and we can discuss how we could help you build your collection.

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