GOLD AND SILVER

                                                                GOLD 

Who hasn’t heard about gold? From childhood and beyond, the word “gold” means wealth and power to most people. So practically everyone gets interested whenever the word “gold” is mentioned. 

Gold is a “noble metal,” meaning it does not rust nor lose its shine. 

Gold occurs naturally in the Earth’s crust and can be concentrated via three main processes; namely, 1) magmatic activity (= molten rock), 2) hydrothermal activity (= driven by heated underground magmatic fluids, e.g. hydrothermal veins), and 3) metamorphic activity (heat and pressure). 

There is also a fourth process: placer deposits, on the Earth’s surface, and involves  weathering/transport plus reworking via running water. 

 

Note: “Porphyry” gold deposits are associated with low-grade igneous intrusions in the 

Earth’s crust.

Primary gold is referred to as lode, whereas reworked gold (i.e., occurs in stream and river beds) is referred to as placer deposits. 

“Porphyry gold deposits” are associated with low-grade igneous intrusions. 

Gold can also occur in “greenstone belts,” which are metamorphosed volcanic and sedimentary rocks, like the “Banded Iron Formations (BIFs).”

In sum, there is a considerable amount of terminology associated with “gold deposits.” 

The value of gold varies daily these days. As of March 21, 2026, the price of gold was approximately $4,504 dollars per ounce! Next week, no doubt, it will have a different value! 

          Figure 1. A hand-specimen of gold (2.5 inches wide). Image via the Smithsonian Institution.

                                                                   Silver

                                                                          

         Figure 2. A hand-specimen of gold (dimensions unknown). Image via the Smithsonian Institution.                       

                                                                  

Silver, whose chemical designation is “Ag,” occurs mainly with hydothermal-veiw deposits, which are commonly associated with igneous intrusions and volcanic activity. Silver is rarely found as a pure, native metal. Rather, it is usually combined with sulfur, arsenic, and antimony, and especially in association with lead-zinc and copper nickel ores. Furthermore, most silver is produced as a by-product of copper, lead, and zinc refining.

REFERENCE 

WIKIPEDIA, 2026

CHRISTMAS CACTUS

This “False Christmas Cactus,” is scientifically named Schlumbergera truncata, a succulent that blooms around November (rather than December). Thus S. truncata also goes by another common name, the “Thanksgiving Cactus.”

Schlumbergera truncata is indeed a cactus and it has sharp, pointy edges with claw-like tips. This cactus also displays flowers from mid-November to early December. Additionally, this cactus has leafless, flat, segmented green stems (caldodes) which act as photosynthetic organs. The ends of these stems are truncated, rather than pointed. The flowers of this cactus can be in shades of pink, orange, or whitel.

This cactus is endemic to a small area of the coastal mountains of south-eastern Brazil, in the state of Rio de Janeiro, where subtropical or tropical moist forests exist. (Wikipedia, 2026).

This cactus is commonly grown indoors to help improve air quality by filtering out airborne toxins, such as formaldehyde, benzene, and xylene.

  Classification

Kingdom Plantae

Clades (3 of them)

Order Caryophyllales

Family Cactaceae

Genus Schlumbergera

Type Species: S. truncate

                                                     Figure 1. Wide view. My backyard. 

Figure 2. Tall view. 

SPECULAR HEMATITE

Should this mineral be called “spectacular” hematite?  It is highly prized by collectors for its sparkle (as seen in Figure 1). Its chemical formula is Fe2O3 [= ferric oxide]. Hematite is the most important and widely used source mineral for iron. This mineral is mainly a sedimentary mineral, which gets altered by ground water. The hardness of this mineral is 5 to 6. It can be polished (as a gemstone) even though it is easily scratched or chipped. It also readily alters to the iron-mineral limonite.

Hematite is the most important and widely used source mineral for iron. More that 90 percent of iron in the USA is from hematite ore.

There are three types of hematite: shiny black (= specular hematite), brownish, and blood red. Vast deposits of it occur in the Lake Superior area. It is also found from New York to Alabama, as well as England, Switzerland, Italy, and Brazil.  The extensive Clinton iron beds of late Silurian age crop out over a length of about 700 miles in New York, Pennsylvania, and Alabama.

Figure 2 (see image below) refers to one way this mineral is determined: rub it on a streak plate (this is a common practice among mineralogists because certain minerals have a distinctive streak color, which can be different than the exterior color of a mineral).  

References

Berrry, L.G. and B. Mason, B. 1959. Mineralogy. Concepts, Descriptions, Determinations. W.H. Freeman and Company. San Francisco. 630 pp.

Sorrell, C.A. 19xx. Rocks and Minerals. Golden Nature Book. A field guide to rocks and minerals. Golden Press, New York. 630 pp.

Figure 1. Specular hematite. 43 mm length, 23 mm width.

Figure 2. The reddish residue left by hematite when it is rubbed against a two-inch long  “streak plate” [consisting of  porcelain]. Streak plates are commonly used in the identification of minerals.

GEOLOGY OF GRAND CANYON and COPPER CANYON

                                                                                            GRAND CANYON

Grand Canyon is formed by a single river, the Colorado River. This canyon is 4,674 feet deep and 277 miles long. The ages of the rocks in this canyon range from Precambrian to Pennsylvian/Permian, with a combined duration of 1.8 billion years.

By the way, there is a commercially available, rubber-raft (or wood boat)  trip down through the Grand Canyon.

Figure 1. A representative portion of the Grand Canyon, Arizona; image by R. L. Squires, Sept. 1973.

                                                                                          COPPER CANYON

Copper Canyon is a scenic area in northwest Mexico, in the state of Chihuahua and is always compared (online at least) to the Grand Canyon in Arizona, USA. The name “Copper Canyon” is derived from the copper-green hue of some of its canyon walls.

By the way, it is possible to take a commercial train through the Copper Canyon area, which has extensive Douglas Fir, pine, and oak trees along the route.

  

Copper Canyon is actually a misnomer. It is not a single canyon, rather it a network of six separate canyons with many side canyons. The deepest part of canyon network is 6,136 feet.

Copper Canyon encompasses about 25,000 square miles, that together is four to seven times the size of the Grand Canyon (depending on how you map the Copper Canyon area).

Cooper Canyon rocks consist primarily of explosive volcanic ash flows, mudflows, and breccia (angular conglomerates), deposited approximately 20 to 40 million years ago during early Eocene to early Miocene time. 

Figure 2. A representative area of a part of Copper Canyon (image modified from an image in the website entitled: images.pexels.com).

STAG BEETLE

Male stag beetles have overzised mandibles that resemble antlers. They are used to wrestle each other for favored mating sites. The females have much smaller bodies and jaws.

Stag Beetle image via public domain.

Stag beetles are not aggressive toward humans. These insects are rare and a symbol of good luck. In some cultures, they are used in for betting/gaming activities (i.e., fighting one another), but not in the USA. In most countries, they are rare and a symbol of good luck.

The fossil record of these distinctive insects ranges from late Middle Jurassic (Callovian) [176 million years ago] to recent.

Kingdom Animalia

Phylum Arthropoda

Class Insecta

Order Coleoptera

Family Luncanidae

Genus Lucanus

There are many species; for example, in the USA alone, there are 30 species.

Reference

Wikipidea, 2026

MOLA FISH: AN UNFORETABLE ANIMAL

This large fish lives offshore, near the surface, in warm oceans. It is not a common fish. They typically lie on their side and move slowly by slapping their dorsal and anal fins in alternation.

Their length is usually 4 to 8 feet, with 11 feet the maximum. They

can weight up to 600 pounds. Their large, dorsal and anal fins characterize this fish. When viewed from above, they have the shape of a "coin"--wide but very narrow. But viewed sideways, they have a large surface area, and they look like a fish "chopped in half." They typically lie on their side, near the surface (as if they are sunning themselves).

They eat mainly squid and jellyfish. The Mola fish is no threat to humans. 

   Classification

Kingdom Animalia

Phylum Chordata

Class Actinopterygii

Order Tetraodontiformes

Family Molidae

Genus Mola

Type species: M. mola (Linnaeus, 1758).

References

Reader's Digest, 1982. North American Wildlife. Pleasantiville, New York. 615 pp. 

Wikipedia. 2026. Mola mola.

all the following images are public domain images

Mola mola in motion.

Mola mola (showing the detail of its skin).

A "captured" Mola mola.

THE MOLE RATS

There are two types of mole rats (both small in size): the naked mole rat and the Damaraland mole rat.

Both are unique small rodents and live their entire lives underground, in burrowing eusocial colonies in Africa. These colonies are like those found in eusocial colonies of ants, termites, and bees. Similarly, fhere is also only a single queen in each mole colony. 

Both kinds of mole rats have no external ears and very tiny eyes (because they live all their lives underground, eyes/sight is not that important). 

The naked mole-rat, which lives in grassy, semi-arid regions of East Africa, is hairless with wrinkled skin that is red grayish-pink in color. This kind of mole rat can live up to 30 years.

                                            

Figure 1. Two views of a naked-mole rat: Heterocephalus glaber (about 3 inches long).

                          Figure 2. Inside view of the underground colony of H. glaber = Naked Mole Rat.

Figure 3. An adult Fukomys damarensis = Damaraland Mole Rat, which lives in Southern Africa, has short black/gray fur--along with a white patch at the top of the head. 

Both types of these mole rats have a long lifespan (up to 30 years). They are most closely related to porcupines and guinea pigs, than to true moles or rats. Both type of these mole rats have powerful teeth used to dig underground tunnel systems.

The Smithsonian National Zoo and Conservation Biology Institute has a cam for the public to view a live colony of mole rats (if the cam is working).

                                   Classification

Kingdom Animalia

Phylum Chordata

Class Mammalia

Order Rodentia

        --------------------------------------------------------------

Naked Mole Rat:                         Damaraland Mole Rat:

Family Bathyegidae                     Family Bathyegidae

Genus Heterocephalus                 Genus Fukomys

Species glaber                                Species damasrensis