DALLAS, TX.- A stunning Crystallized Gold on Quartz (est. $70,000-100,000) is expected to vie for top-lot honors in Heritage Auctions' Nature & Science Auction May 5-6 in Dallas.

The specimen comes from a preeminent source of fine American gold specimens, Eagle's Nest Mine (Mystery Wind Mine) in Sage Hill in Placer County, California, and features a magnificent leafy sheet of gold sitting atop a shapely matrix of white quartz. The gold "spray" exhibits good octahedrons, adding to the charm of the piece that would fit well in any serious collection. The gold sheet measures a full five inches at its longest point.

"Beautiful gold specimens always draw shrewd collectors, and this auction has eight gold lots for collectors at all levels," said Craig Kissick, Director of Nature & Science at Heritage Auctions. "We also have a really wide array of collector-grade mineral specimens, including numerous colorful crystal examples that show the range of ways in which nature can produce stunning art."

A massive Gold Nugget (est. $30,000-50,000) from the Bendigo Goldfields in Victoria, Australia, is exceptionally attractive from any angle. The color is brilliant, which is the result of a beautiful luster and expert preparation. Weighing a hefty 22 troy ounces, it includes minor embedded white quartz within a few crevices.

A Rhodochrosite with Quartz & Sphalerite from the Hedgehog Pocket in the Sweet Home Mine in Mount Bross, in Park County, Colorado (est. $30,000-50,000) is considered a world-class sample. This cluster features numerous rhombohedral crystals of the "gemmy" watermelon-red mineral, including a relatively large and complete crystal centrally located in the association that also includes an amazing crop of fibrous quartz crystals and other metallic minerals, including Sphalerite and Pyrite.

In a merging of nature and art, Quartz "The Shard" from Brazil's Minas Gerais (est. $30,000-50,000) brings to life the vision of artist Lawrence Stoller, who is very well known in the collecting community for his work with geological specimens. This massive (six feet tall) crystal, featuring white quartz, smoky quartz and feldspar presents on a metal armature integrated into the form of this extraordinary work of natural art.

Another striking Rhodochrosite, from the N'Chwaning Mines in the Kalahari manganese field in Northern Cape Province in South Africa (est. $30,000-50,000), boasts an elegant cluster of cherry-red Rhodochrosite crystals from South Africa. These well-formed crystals display amazing luster, color and "gemminess." The large scalenohederal crystals have a truncated termination, where the tips are flattened. The intense red hue is due to a high concentration of manganese inclusions. When this "flower" is flipped over, the backside also is appealing, as the contact point is visible, and it becomes evident how this stunning piece grew. Also worth noting is the internal visible structure in the transparent crystals, which appear almost as white phantom crystals.

An extraordinary specimen of Aquamarine (est. $30,000-50,000) from the Shigar Valley in Pakistan boasts two large aquamarine crystals that have grown into an aesthetic "V" shape on a bed of tabular creamy Albite. The crystals have gorgeous form with sharp, lustrous "gemmy" faces, and are tightly inter-grown to the point that they effectively form a single crystal.

"One appealing aspect of this auction is the fact that the specimens in the second, non-floor day of this auction also are exceptional examples which simply are being offered in a second session," Kissick said. "They are not inherently of lesser quality or value than the pieces in the front of the catalog."

Other top lots include, but are not limited to:

· Crystallized Gold in Quartz from Eagle's Nest Mine in Sage Hill, California (est. $25,000-35,000)

· Amethyst Geode from Uruguay (est. ($25,000-35,000)

· Iron, IAB from the Maritime Territory in Siberia, Russia – witnessed fall: Feb. 12, 1947 (est. $25,000-35,000)

· Mimetite from San Pedro Mine in Chihuahua, Mexico (est. $20,000-30,000)

· Opalized Belemnite from Coober Pedy in Australia (est. $20,000-30,000)

· Tourmaline from San Diego Co. California (est. $20,000-30,000)

· Orbicular Granite from Boogardie Station in western Australia (est. $20,000-30,000)

· Campo del Cielo Meteorite Iron, IAB-MG Chaco, Argentina ($20,000-30,000)

· Pyrite Cluster from Huanzala Mine in Peru (est. $20,000-30,000)