GIA Symposium Poster: for Gem Dealers who want to sell Mineral Specimens.

Last week I attended the 6th GIA Symposium, which was about research and business of gem materials. I mainly attended the research track, especially colored stone and pearl research. I also was able to attend the field trip to some Pala mines prior to the Symposium.

My poster, intended for gem dealers, explains what mineral collectors are looking for in a specimen. Some gem rough can be sold as mineral specimens, but the proper material must be recognized and marketed appropriately.

The images are from Rock Currier, and are copyrighted by him. These can also be found on the mindat.org website.

Email me at mlj@cox.net if you would like a copy of the PDF file.

3a. The Evils that beset mineral collections: Temperature changes

In the last installment, I discussed temperature effects, but not temperature change effects.

The largest effect happens in situations where a collection is kept in places that can get below the freezing temperature of water. There is an effect called freeze-thaw disaggregation, which is seen in nature at rock outcrops: water seeps into the rocks and expands as it freezes, prying the rock apart. Minerals with fluid inclusions, or ones that are inadvertently wetted down (does your basement flood?) might suffer from such effects.

The other extreme is rare as an environment, but can occur to specimens with fluid inclusions when viewed through a microscope with hot lights, or while being photographed with hot lights. Some fluid inclusions contain gas bubbles (e.g., carbon dioxide bubbles), and these expand as a specimen is heated. In one anecdotal case, a gemstone exploded when held in someone's mouth.

Temperature cycling can also cause a mineral specimen to disaggregate. Each mineral has its own thermal expansion coefficient, which measures how much it expands as it gets hotter and contracts as it gets cooler. Anisotropic minerals (corundum is a good example) have different thermal expansion coefficients in different directions, and can even contract in some directions while being heated.
A matrix mineral specimen is an aggregation of different grains, often with varying orientation. The grains will typically push against each other as temperature climbs, and pull apart as temperature falls. This might lead to delicate specimens falling apart.

3. The Evils that beset mineral collections: Temperature and Temperature changes

Is global warming a threat to your mineral collection? Maybe.

First, let's talk mineral stability. Many mineral species are described that are not stable at room temperature, pressure, and humidity. However, most are stable in the environments in which they form (some are formed metastably, which won't be discussed more in this blog entry).

To form, minerals need a supply of nutrients (elements), and the appropriate pressure and temperature ranges. The conditions needed for mineral stability also include the relative amount of water available, relative acidity, and oxidation state. Minerals that contain other elements that may be in the gas or fluid phase, such as sulfur, selenium, and fluorine, may have additional requirements for stability.

Now look at minerals that are outside their stability range. Will these immediately decompose? Not necessarily. If the amount of energy needed to start the change or decomposition is high, the mineral may stay in the same state despite adverse conditions. This is called a metastable condition, and the best example is diamond.

However, many minerals do break down, and the conditions on earth that form minerals may not be represented in your collection. The most obvious low-temperature example is ice; another is antarcticite. Neither of these are stable at 20-25 C.

The opposite case is for high-temperature minerals whose crystal structures spontaneously distort at lower temperatures. Probably all so-called specimens of "beta quartz" are now alpha quartz, unless there is a mineral collection that keeps specimens above 550 C.

2. The evils that beset mineral collections: Space

Space, or lack of it, is often a problem for compulsive collectors like me. As zen comedian Steven Wright said, "You can't have everything. Where would you put it?"

Here are some typical space concerns:

Display space: How many of your minerals can be displayed at once? Would you like to display more, and if so, do you rotate the collection so that other specimens are sometimes on display?

What happens when you get new display pieces? Often, the existing display is rearranged to make space for the new specimens. Eventually, display clutter becomes a problem.

Can you see all the specimens on display from one position, or do you have to contort yourself to see what's on a lower shelf, or the items in the corners? If the latter, your display spaces may be too crowded.

Do no specimens touch? Is it clear which label belongs to each specimen? Is every label readable without moving any specimens? If so, you may have enough display space for the specimens you are showing.

Storage space:
Is it archival? Is it secure against rodents, insects, and other pests? Is it secure against theft, weather, and other hazards? These are all reasons that a garage may not be the best place to store some or all of your specimens. Weight and heat may preclude attic storage; water problems may preclude basement storage. You'll have to judge whether any of these will work for you.

For important specimens (or jewelry), you may wish to invest in a box in a bank vault. There are rumors of opals crazing in bank vaults due to lack of humidity, so think twice about storing opals there. You might also wish to save a copy of your mineral records in a remote site such as a bank vault.

Is it accessible? If you need to get access to a particular specimen in storage, it helps to know exactly where it is, and what you need to move to get access to it. It's easy to bury boxes under other boxes, so it's important that every box be labeled on all sides. "This end up" is another important message where needed.

Gemstone storage: For those of you with loose fashioned gemstones, how do you store them? Some people use individual pill-case type containers, some use small plastic bags, and some use stone papers. (Larger specimens or suites are often stored in their own lined cases or Riker Mounts.) Regardless of the storage method, gemstones should not touch each other; even diamonds get "paper wear" from other diamonds in the same stone paper.

1. The Evils that beset mineral collections: Time

How many ways can time damage a mineral collection?
The primary problem is in the retention of information, but minerals themselves can also be damaged.

How can information be lost?

• If you haven't written something down, it can be forgotten. That includes the location of samples and information. Take the time to label your specimens, even if with temporary labels, as you acquire them.
• Sometimes notes (especially receipts) are not prepared using archival materials. Paper crumbles, ink fades, tape becomes unsticky. Try to avoid using non-archival materials; make copies of unstable notes.
• Computer programs become obsolete over time; computer media may not be stable (e.g., many CDs are only rated for 10 years), or their related hardware may become obsolete. (For instance, my Ph.D. thesis is on large-format magnetic tape, and prior to that I used punch cards to index collection information: these are now dead media.) If your information is archived on hard media, update the media regularly, and check that the information has not become corrupted in the meantime; if it is in "the cloud," still make your own backups.
  
• When the time comes to pass your collection along to another place, will you be there to handle the transfer? Or will your heirs know where the specimens are, which have special care issues, which label belongs to each specimen, and who gets what? Collections deserve special attention in the estate planning process. (And does the recipient know the collection is coming? Give your heirs a chance to prepare for the collection's arrival.)
  

What can happen to minerals?

• Over time, minerals can react with their environment. Sharp water soluble crystals can become rounded due to humidity changes over time; some pyrite and marcasite crumble due to bacterial contamination; acid paper reacts with sulfide minerals.
  
• Metastable minerals can revert or decompose: for instance, hydrous (or "hydratable") minerals gain or lose water.
  

Some of these changes can be mitigated with a stable environment and isolation of some specimens; but some is inevitable.

The evils that beset mineral collections: Intro

This next series is on the evils to which mineral collections are heir: the things that make a collection less valuable, or less educational, than it might have been:
1. Time
2. Space
3. Temperature and temperature changes
4. Humidity and humidity changes
5. Vibration and flexure
6. Dust
7. The Sun
8. Natural disasters
9. Moving
10. Insects and other pests
11. Children and other people
12. Loans, trades, and other collectors
13. Sulfur, pyrite, and other minerals
14. Newspaper, tape, glue, and other nonarchival materials
15. Inclination, boredom, lack of discipline, and new worlds to conquer
16. Poverty, death and the disposition of goods and records

Some of these are necessary evils in having both a mineral collection and a life, but let's watch out for them.

Comments are welcome for any evils or other topics you'd like me to mention.

Collection Management V: The Label, Part 3: Localities

The specimen's locality is the most crucial piece of information that can be provided. This is because a mineral's identity can always be redetermined, but its exact locality usually cannot be restored with any certainty.

I recommend that the label contain locality information in as much detail as you can provide: for mines, this includes the level, stope, cross-cut, etc.; the GPS coordinates, if you have them; address, city, township, county, state, etc. If you have not collected the specimen, all this information may not be available; the currently desired minimum information is the county (or equivalent), state (or equivalent), and country (or equivalent).

What about existing labels? I generally make my own label as well (you may want to save the old label in a separate place if it is delicate). Some locality information may be out of date (e.g., "Czechoslovakia" or "USSR").

For localities, don't add new information that did not come with the specimen, unless you can indicate on the label that you are doing so. One way is to put the new information in brackets, ideally with your initials labeling the change:

[Czech Republic]mjc, formerly Czechoslovakia

Collection Management - II

Each item in a collection needs:

• a unique descriptor (e.g., specimen number),
  
• an accompanying label,
• a permanent record,
• and safe, accessible storage.
  

In this post, I will discuss the unique descriptor.

Typically, this is a unique number assigned to the specimen. It may also be an alphanumeric character string, a bar code, etc.; but a symbol that requires a sophisticated scanner to read assumes that scanning system will be available for the useful life of the specimen (which may be centuries).

For minerals, this number is usually affixed to the specimens, either by writing or painting it on the specimen, or by attaching a printed label with permanent glue.

For loose gemstones, typically each gemstone has its own box, and a label with the descriptor is affixed to the box. As the label is not physically attached to the stone, it helps to include the gemstone weight on its label as a quick (but not exact) check for its identity.

Every record for this specimen should include the descriptor. Descriptor should not be used for more than one specimen (except in the case of bulk samples, where each bulk sample needs a unique descriptor, and individual grains in the sample only need separate descriptors when they are separated out for some purpose, like research or display). Descriptors should never be reused, since even if a specimen is destroyed, lost, or traded away, its records should remain with the collection.


I provide collection management services professionally, so feel free to contact me!