What is a mineral? A mineral is (generally) an inorganic, naturally occurring, organized crystalline structure composed of a single chemical compound or element.
What is a rock? A rock is (generally) a natural solid composed of multiple crystals of one or more minerals. Although many rocks contain visible crystals of individual minerals, a rock itself does not have an overall crystalline structure.
What is a crystal? A crystal is an orderly arrangement of molecules formed because the component atoms and ions tend to aggregate together in certain specific patterns. Sometimes very different minerals are formed from the same starting materials (such as diamond versus graphite, both pure carbon) as determined by the temperature, pressure, or other conditions of formation. These arrangements result in the crystal forms described in the physical characteristics pages. Often, minerals are formed as a solution changes in some way which allows or forces the component mineral(s) to solidify or precipitate out of solution. This change may be temperature, pressure, chemistry, or concentration, and the solution may be aqueous or a magma (or even a gas, as sulfur crystals may condense from vapors emitted by a volcanic fumerol, and snowflakes precipitate from air). A slow solidification or precipitation supports the growth of larger crystals. Note that this process is responsible for much of the mineral segregation that gives us ores, as well as all of the gemstones we admire. Crystals may be too small to see, as in agate, or incredibly large - see our Gypsum page for an astounding example. Of course, not all solids are crystalline. Very rapid cooling of a molten compound can result in a glass, where the individual molecules have random orientations, not the orderly arrangements found in a crystal.
Before the Earth was formed, before igneous or sedimentary or metamorphic rocks were even possible, there were primordial rocks and primordial minerals. In the early solar system these condensed directly from the solar nebula, and are visible today as asteroids and comets in space, and as meteorites on Earth. Indeed, the number of distinct minerals appears to have increased over time: see The Evolution of Minerals.
*** NOTICE ***
We are now running on a new, upgraded server (both hardware and software), hosted on a new server farm. There is a known problem with my Search function. Thank you for your patience and understanding as I find and fix the remaining problems. Please email me (email@example.com) if you find a page that should be corrected.
Amethyst Galleries' Mineral Gallery
describes over 600 mineral species and 5,000 specimens
(see our new specimens last updated
We apologize if any of the ads displayed on our site seem inappropriate. While most are properly related to gemstones, minerals, and rocks, we can't control which keywords the advertisers target, plus this site is very popular (averaging 300,000 visitors per month) and is chosen by hundreds of advertisers who seek customers such as you. Recently, Google has chosen to present ads based upon past searches conducted by visitors such as you, and those ads also have nothing to do with this site. Feel free to give Google feedback via the "Feedback - Ads by Google" link at the corner of many of their ads.
Note that, for your convenience, the ads and menus will not display in printed pages for modern browsers.
Our favorite specimens are marked with this symbol, and those that are still available for purchase are listed on our Favorites Page. Check out our new Minerals By Price pages, where you can easily find minerals under $10, between $10 and $20, or even over $1000!
We are having an Inventory Clearance Sale! Select specimens are from 10% to 50% or more off. See the By Name lists, and click on the Sale! links to jump to the first "on sale" specimen for each mineral. Or, see our By_Discount page which provides direct links to specimens at a given discount - your index to great bargains.
|Encyclopedia Britannica selected|
Amethyst Galleries' Mineral Gallery
as one of the Web's Best Sites for 2009!
||We accept payment using PayPal, a highly secure and widely trusted payment processor. If you have any questions, problems, suggestions, or comments, please e-mail them to firstname.lastname@example.org.|
To purchase our specimens, select a mineral using any of the indexes, and then choose the Specimens link (or use the specimens shortcut on the By_Name index). This will usually display several available specimens, some of which may be marked Sold or Sale Pending, but others will have an Add To Cart link which will add that specimen to your shopping cart. You may Cancel or Proceed to Checkout your order then, or after further browsing. Generally, you will return here to View Shopping Cart (if any), and from there you will Cancel it or Proceed to Checkout. Shipping is normally the next business day (with 3 to 5 days delivery time for most North America destinations). For more information (including our address), see the page How to Buy From Us.
Do you have comments, suggestions, or requests about this service? Please provide us with feedback; we would appreciate it!
About Amethyst Galleries, Inc.:
To learn more about this service, check out our About page!
Our phone number is (904)662-0520. You may also contact us by e-mail as follows: