Friday, June 20, 2008

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. 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!!

Sunday, June 15, 2008


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!!!

Thursday, June 12, 2008

"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: or Chris Ward at: 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!!