Because You Asked

Del Air member Dodd Roth asks:

Do you know of any gypsum mines that have colored rocks?

"Because You Asked" answers:

None that I know of personally, however, there are literally thousands of gypsum deposits around the world...stretching from Antarctica to the Siberian Steeps. Few are mined for anything other than industrial purposes but some collector specimens seem to be collected at a high percentage of them. Though the crystals are colorless to white, many deposits will have mineral associations that can color gypsum in an assortment of shades depending on what the associated minerals are. Mindat.org has a large gallery of gypsum photos from almost 100 locations that show several different colors. Massive forms (lapidary rough) of gypsum can also have a lot of color variation, probably more so than that of crystals. I do not know and can not find a list of commercial gypsum "lapidary material" locations, but If such a list exists it would most likely be a long one.

Thanks for asking!!

"BECAUSE YOU ASKED"

Del-Air guest attendee, Richard Leyton, asks:

I am looking forward to going on the Mt. Gleason field trip on June 21st. The bulletin says to bring light digging tools. What does that mean? A prospector's pick? A gardening trowel? A 6 foot shovel? A full size pick ax?

Thanks, Richard Leyton

'Because You Asked' answers:

Light digging tools would refer to rock hammers, chisels, small garden trowels, crow bars etc. Basically hand sized tools. Also a spray bottle filled with ordinary water to spritz down your specimens to better identify what you are bringing home. Bring a pair of safety goggles to protect your eyes when hammering rocks. I carry one of each of these hand sized tools in a canvas tote bag with handles whenever I go rock hounding. The bag is large enough to hold the rocks I want to bring back as well. A heavy duty back-pack would work too.

Heavy digging tools would refer to full size pick-axes, sledge hammers, full size shovels and industrial size pry bars. These, however, are much more unwieldy and are difficult to lug around especially whens it really hot.

Don't forget to bring food and plenty of drinking water so you stay hydrated. Watch out for snakes and keep an emergency first aid kit in the car.

I hope this answers your question and provides you with a few tips as well.

Till next time...........Happy Rock Hounding!!!

"Because You Asked"

June's mineral of the month, Calcite, elicited a fair amount of oohs and aahs, as members and guests had an opportunity to examine the several beautiful and extremely different examples of this relatively common mineral. Hopefully this new feature of the Del-Air Rockhounds Club is being enjoyed and we are all learning something new.

This brings us to yet another new feature of the club, "Because You Asked". If anyone ever has a question regarding rocks, minerals or other rock hounding subjects that can not be answered while at our monthly meetings, simply e-mail your question to Bob Knox at: rknox1@socal.rr.com or Chris Ward at: chris_ward678@yahoo.com and your query will be researched and answered right here in your blog. Questions may be submitted at any time and members and interested guests will receive an e-mail notification stating the answers have been posted to the blog.

And now....for our first question....

Mrs. Paul O'Connor asks...."In the information handout for the June 2008 Mineral of the Month, Calcite, the word 'gangue' appeared in the mineral's description. What does this word mean?

"Because You Asked" answers:

Ore and Gangue: The general definition of “ore” is a naturally occurring material from which minerals of economic value can be extracted at a profit. For example “gold ore” or “iron ore”. Ore minerals are the specific minerals containing the commodity of interest. Many minerals contain elements of commercial interest, but are not ore minerals because the mineral is “refractory”, meaning it is difficult or impossible to extract the commodity from the mineral. Gangue (pronounced like 'gang') minerals refer to the material so intimately associated with the ore that it has to be mined along with the ore and is later removed by various crushing, grinding and separation processes. The “host rock” is the rock surrounding the ore and gangue, which has no value. To illustrate these relationships, consider the following example for a gold ore:

A gold-bearing quartz vein 1 foot thick occurs in a granite intrusion. The quartz vein contains arsenopyrite and pyrite in addition to native gold. The “ore” in this example is the quartz vein that contains concentrations of gold. The ore mineral is the native gold. The gangue minerals are quartz, arsenopyrite and pyrite. The granite is the host rock.

Thanks for the questions and keep them coming!!

Del Air Rockhounds Present............

June 2008 Mineral of the Month

Calcite

Found in most geologic settings and, in one form or another, as a later forming replacement mineral in many other environments . It is most common as a massive material in limestones and marbles. It forms as chemical sedimentary deposits in limestone and can be regionally metamorphosed into marbles. Calcite is also a common gangue mineral in hydrothermal deposits. Its crystals are rhombohedral and scalenohedral with combinations producing “nailhead” and “dogtooth” forms. Iceland Spar variety shows double refraction. Twinning is very common.

Its chemical properties are as follows:

Mineral Group......................Carbonates
Chemical formula................CaCO3
Specific Gravity...................2.71
Tenacity…………………….Brittle
Color......................................White, Yellow, Red, Orange, Blue, Green, Brown, and Grey
Hardness..............................3
Luster....................................Vitreous, Pearly
Transparency.....................Transparent to Translucent
Streak....................................White to Greyish
Cleavage..............................Perfect
Fracture...............................Subconchoidal

Del Airs Prove To Be Most Popular Once Again!!

The Del Air Rockhounds booth once again proved to be the most popular attraction at the Our Community Charter School's Spring Fair. The day was sunny and bright and not too hot with a nice cool breeze blowing all day long. Del Air members showed up in force to help man the booth. A big and hearty THANK YOU goes out to Bob & Maxine Dearborn, Julie & Oscar Marin, Hiro Matsuo, Len & Ethel Hellenthal, Jeff Dengrove, Bob Knox and Chris Ward. A very special THANK YOU goes out to Ben Fullon and Richard Quezada, two potential new Del Air members, who sacrificed their time to help us out on this event. Ben spent the entire day manning the "What Is It" table helping youngsters and grown-ups alike identify the many amazing rocks we had on display. Richard wasted no time getting down and dirty with the tile saw and in no time was quickly slicing open geodes like a pro. Their participation is greatly appreciated.


















As always, the "Spin-a-Wheel", manned by Ethel, Len and Hiro attracted quite a few people as well as the "Paint Your Own Dinosaur Claw" table expertly handled by Julie, Oscar and Maxine. Bob Knox lent a hand wherever and whenever it was needed. Myself, Jeff, Bob Dearborn and Richard worked the geode cutting table. We all had a blast and ended up raising a goodly amount of money for both the school and our club as well.