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About Geodes

The Rock Professor has provided you with a mineral
information card.  Print on stock paper, and cut out to
enhance your rock and mineral products.

To print: with your cursor, highlight the entire card below,
right click and select print, then click on "selection"
and print.

THE ROCK PROFESSOR

 

Example of a geode in The Rock Professor

 

Composition:
may include
quartz crystals, 
amethyst  crystals,
agate, chalcedony,
jasper, calcite,
dolomite, celestite.

Prevalence:
U.S., Brazil,
Namibia, Mexico


Cathedrals, amethyst:
large to very large 
geodes lined with
amethyst crystals

GEODES


GEODES are spheroidal to eccentric-shaped rocks formed when minerals either enter or are trapped in openings or voids inside preexisting rock material. In volcanic rocks, fluids and gases often remain inside air pockets in the lava. During and after cooling, these fluids, from the outside in, fill the cavity with various successions of agate and quartz layers, often ending in open cavities with inward-facing quartz crystals. Other geodes may be formed by cavities formed by dissolved organic material, fractures in the rock, or by pockets caused by dissoved mineral material. These geodes will often have tapered layers that lead to in "inlet", where the filling solutions entered the cavity.

Rarely, a geode will be partially filled in the center by a horizontal sequence of layers inside the concentric bands, ending in a flat surface. This is a gravity filling of the cavity with materials probably under less pressure, ending when there are no more fluids. You can tell which way was "up" when the geode formed.

Colors within the geodes are caused from elements, such as iron, that are carried in the solutions. Most geodes are composed of agates, a member of the quartz family, although some geodes are formed of calcite, usually in limestone pockets.

Results 1 - 32 of 54
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About Geodes

Agate Bookend, Purple BE 2088

Agate Bookend, Purple BE 2088

Sales price: $85.00

Product details

Agate Geode Pair Teal GEO 2057

Agate Geode Pair Dyed Teal GEO 2057

Sales price: $20.00

Product details

Agate Geode, Dyed Blue - GEO 2226

Agate Geode, Dyed Blue - GEO 2226

Sales price: $10.00

Product details

Agate Geode, Dyed Blue GEO 2302

Agate Geode, Dyed Blue - GEO 2302

Sales price: $27.00

Product details

Agate Geode, Dyed Blue GEO 2303

Agate Geode, Dyed Blue GEO 2303

Sales price: $28.00

Product details

Agate Geode, Natural - Stand, GEO 2132

Agate Geode, GEO 2132

Sales price: $15.00

Product details

Agate Geode, Natural GEO 1624

Agate Geode, Natural GEO 1624

Sales price: $12.95

Product details

Agate Geode, Natural GEO 1627

Agate Geode, Natural GEO 1627

Sales price: $12.95

Product details

Agate Geode, Natural GEO 1879

Agate Geode, Natural GEO 1879

Sales price: $11.00

Product details

Agate Geode, Natural GEO 1880

Agate Geode, Natural GEO 1880

Sales price: $11.95

Product details

Agate Geode, Natural with Base GEO 2200

Agate Geode, Natural with Base GEO 2200

Sales price: $54.00

Product details

Agate Geode, Natural, Cut Base - GEO 2223

Agate Geode, Natural, Cut Base - GEO...

Sales price: $32.00

Product details

Agate Geode, Natural, Cut Base GEO 2301

Agate Geode, Natural, Cut Base GEO 2301

Sales price: $20.00

Product details

Agate Geode, Natural. GEO 1271

Agate Geode, Natural. GEO 1271

Sales price: $9.95

Product details

Agate Slice on Wood Base DEC 2089

Agate Slice on Wood Base DEC 2089

Sales price: $16.50

Product details

Agate Slice, Natural - Stand, SL 2238

Agate Slice, Natural - Stand, SL 2238

Sales price: $18.00

Product details

Amethyst Agate Geode GEO 1974

Amethyst Agate Geode GEO 1974

Sales price: $96.00

Product details

Amethyst Agate Geode GEO 2013

Amethyst Agate Geode GEO 2013

Sales price: $52.00

Product details

Amethyst Agate Geode GEO 2015

Amethyst Agate Geode GEO 2015

Sales price: $110.00

Product details

Amethyst Agate Geode GEO 2031

Amethyst Agate Geode GEO 2031

Sales price: $75.00

Product details

Amethyst Agate Geode GEO 2097

Amethyst Agate Geode GEO 2097

Sales price: $98.00

Product details

Amethyst Geode Sphere POL 829

Amethyst Pocket, Agate Sphere POL 829

Product details

Amethyst Geode Sphere POL 840

Amethyst Pocket, Agate Sphere. POL 840

Product details

Amethyst Geode Sphere POL 841

Amethyst Pocket, Agate Sphere. POL 841

Sales price: $82.00

Product details

Celestite Geode Egg POL 1445

Celestite Geode Egg POL 1445

Sales price: $16.95

Product details

Celestite Geode, Madagascar GEO 1929

Celestite Geode, Madagascar GEO 1929

Sales price: $92.00

Product details

Dugway Geode Free Form GEO 1709

Dugway Geode Free Form GEO 1709

Sales price: $27.50

Product details

Dugway Geode Free Form GEO 1712

Dugway Geode Free Form GEO 1712

Sales price: $77.00

Product details

Dugway Geode Free Form GEO 1713

Dugway Geode Free Form GEO 1713

Sales price: $82.00

Product details

Dugway Geode GEO 2061

Dugway Geode GEO 2061

Sales price: $14.00

Product details

Dugway Geode GEO 2073

Dugway Geode GEO 2073

Sales price: $20.00

Product details

Dugway Geode, Cut Base GEO 1659

Dugway Geode - Huge, Cut Base GEO 1659

Sales price: $325.00

Product details

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Conditions:

· Merchandise may be returned within 10 days of the date of receipt.
· Returned items must be in original condition
· Goods must be in their original packaging.
· Upon receipt of the return, we will credit the card you used for payment for the amount of the purchase, less shipping.