Quartz is one of the most abundant minerals found on earth, in sedimentary, metamorphic, and Igneous rocks. It's also one of the most durable minerals, which is why it is so abundant on many beaches. Here is a list of many of quartz's forms:

Algae Jasper- A local name for jasper found in the northern counties of Minnesota. Bright red with a cell-like pattern.
Amberine- A yellowish-green chalcedony from Death Valley, California.

Amethyst   

Amethyst- A pale lavender to deep purple transparent variety of quartz.
Amethystine- Sometimes called azure quartz and sapphire quartz. This is usually an opaque type of amethyst with mixed shades of color from lavender to purple.

   Phantom Quartz

Apricotine- Trade name for yellow to apricot colored quartz pebles found near Cape May, New Jersey. Sometimes occurs as reddish-yellow.
Arkansas Stone- A pure white, porous rock containing millions of minute quartz crystals cemented with chalcedony and known to minerologists as novaculite. It's chiefly used as whet stones.
Auriferous Agate- An uncommon light agate containing gold. Occurs as stream pebbles.
Aventurine- A translucent green quartz containing very small inclusions which produce a glittering sheen and spangled effect. The inclusions vary. Mica inclusions produce a silvery, brassy, or golden glitter called aventurescence. Guchsite inclusions produce a greenish aventurescence. Hematite or goethite inclusions produce a metallic reddish appearance. Aventurine may be gray, yellow, brown or green, but only the green variety is preferred as a gem and it is always cut as a cabachon(a cut shown in the picture at the top of this page).

Worm enclosed in banded agate   

Banded Agate- Agates with colors usually arranged in parallel bands, which are usually wavy. Most of the agate in the trade is this variety but it is dyed or heat-treated. Sometimes called Riband Agate.
Basanite- A deep velvety-black variety of amorphous quartz, slightly tougher and finer grained than jasper.It is Touchstone, which is used by jewelers for testing precious metals. It's widely distributed and associated with jasper in gravel deposits.
Bavarian Cat's-eye- Quartz cat's-eye from Hof and other locations in Bavaria which produce only a few stones of fine quality.
Bayate- A local name for a brown ferruginous variety of jasper from Cuba.
Aeckite- The star pattern of coral geodes of Panama.
Binghamite- Crystalline quartz containing replacements of goethite. When polished, the gem exhibits a decided chatoyance due to the light reflections of the embedded fibers. It sometimes produces fine cat's-eye gems. It's reported to be 98% pure quartz. The inclusions appear in straight lines. A similar material is silkstone, but this material is not as nearly pure quartz and the inclusions are not straight.
Black Chalcedony- The correct term for black onyx. It is usually a dyed, clear chalcedony, the black color being produced by boiling it in a sugar solution. The true onyx has white stripes in it.
Blood Agate- A cabachon material from Utah in flesh-red, pink, or salmon colors. It's sometimes called hematite.
Bloodstone- Dark-green jasper with lood-like red spots.
Blue Agate- A rare color in agate. A light sky-blue color comes from near Ellensburg, Washington.
Boakite- A local name for a brecciated green and red jasper found in Nevada. Breccia refers to a rock that contains broken pieces of another rock.
Botryoidal Agate- Small spheres of agate resting on a matrix.

   Breccia cabachon

Brecciated Agate- Agate which has been broken into irregular fragments and then cemented together by silica solutions.
Brecciated Jasper- A reconstituted form of jasper in which the patterns appear as mosaics.
Burnite- Not a pure quartz gem, but a very beautiful sky-blue mixture of silicates, oxides, and carbonates of copper. Found near Battle Mountain, Nevada.
Carnelian- A red, orange-red, brown-red or brown colored, translucent to semitranslucent form of chalcedony. It is sometimes yellow or brownish-yellow, and when it grades into brown, it is called sard. When it alternates with bands of white, it is called sardonyx.
Carnelian Onyx- A term used in a broader sense for any true onyx; one or more of the alternating bands being carnelian in color. Differs from Sardonyx.
Cat's-eye Agate- Due to reflections a coloring, so-called "moonstone" agate will exhibit an opalescence that gives a cat's eye effect.
Cer Agate- A rare chrome-yellow colored agate from Brazil; similar to sard.
Chert- Chemically identical to jasper. Usually, any ugly or interesting jaspers will be called chert. Chert usually refers to impure chalcedony formed by precipitation of silica from geothermal waters. It has been used to make arrowheads for thousands of years, as has flint, which it resembles.
Chrysocolla Agate- Chalcedony in very attractive blue-green to bright-green colors caused by copper silicate inclusions.
Circle Agate- A term used for agate with circular markings.
Cloud Agate- A name applied especially to a light-gray, transparent to semitransparent chalcedony with large spots of darker gray, which resemble clouds.
Concretion Agate- A term applied to the agate portion of the interior of concretions.
Coral Agate- Any agate resembling fossilized coral.
Creolite- A red and white banded jasper found in Shasta and San Bernardino counties in California.

Tigereye Quartz  

Crocidolite Quartz- Same as Tigereye.
Cyclops Agate- An eye agate with only one eye.

The above agatized thunderegg was found at Bob's Rock Shop where several more beautiful specimens can be seen.

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