Thursday, March 31, 2011

Miscellaneous: Skunk with garlic

Smells have an umbra and a penumbra. (These terms are taken from astronomy and mean "shadow" and "almost shadow", respectively.)
When you are reasonably close to a source of strong odor (that is, in its penumbra), it has a distinctive smell: like incense, cat-litter boxes, or, in particular instance, skunks.
However, when you are really close, in the umbra, the odor takes on many nuances, and can change entirely. One can detect the match flare in the incense, the catfood post-processing, etc. In the case of our recent nocturnal visitor, the skunk:
--strong skunky mercaptans
--raw sulfur
--strong green onions (you know the ones that are really too big, but you eat them anyway?)
--and really really strong raw garlic.
Under our bedroom, two nights ago.

I got to sleep by mentally completing the recipe: the skunk needed basil and oregano, tomato sauce, and to roast those garlic slices in olive oil until slightly brown before adding to the sauce.

(Last night she was less panicky, so less stinky.)

Monday, March 28, 2011

The evils that beset mineral collections: 6. Dust

Is dust evil? It seems omnipresent; but dust can create serious problems for your mineral collection in two ways: by its accumulation and by its removal.

The contents of dust varies with environment. Dust in the outdoors or a garage is rich in finely powdered rock flour, as well as pollen and regional pollutants (diesel exhaust, etc.). Indoor dust also contains fine fibers, and may contain tars from smoking. Vaporized oils from cooking, spider webs, and many other things end up as dust.
  • Exhaust material and oils smudge surfaces, leave stains and may be hard to remove.
  • The quartz in rock flour scratches soft mineral surfaces and soft polished gems.
  • Fibers are hard to dislodge from delicate specimens, and are glaringly obvious in microscopy and micro-photography.
  • Thick coats of dust obscure labels and disguise features.
Mineral specimens themselves can give off dust; some species occur as fine powders, and some specimens are friable. The powders could be radioactive, or asbestiform. Protection of a mineral collection also entails protecting collectors and visitors from the collection, so it is important to store powdery, liquid, and radioactive minerals in appropriate closed containers.

Although dust can be bad, removing dust can also damage specimens and their labels. Use great care when cleaning either of these.

Monday, March 21, 2011

The evils that beset mineral collections: 5. Vibration and flexure

Vibrations are waves of movement of the environment around a mineral. These include sound and shaking (from footsteps to earthquakes).
Flexure, or flexing, is bending. Take a pliable material, like a paperclip, and bend it back and forth. Eventually it undergoes metal fatigue and snaps.
  • Delicate mineral specimens can fall apart due to repeated exposure to slight vibrations; know which of yours are susceptible to this, and keep them isolated from shocks. (Look for inexplicable dust around the specimen when it is on display as an indication it is susceptible to vibration damage.)
  • All powdery specimens are susceptible to vibrational damage; keep in closed containers.

  • The vast majority of mineral specimens will be damaged if the case they are in is overturned by an earthquake or comparable large shock. If you live in an area where earthquakes are a concern, consider storing your minerals in individual boxes lined with an archival foam material, like Volara.
  • A heavy cabinet or safe by itself will not protect your specimens from earthquake damage, unless it is securely anchored to bedrock or deep foundations. (Without appropriate securing, the cabinet can become a large heavy projectile.)
  • Raised edges on open shelving, "museum wax," Velcro, and other stabilizing materials can limit the movement of individual items in small or moderate earthquakes.
  • Many websites deal with preparing for earthquakes. In general, large heavy items should be kept on low shelves, and certainly not over one's head.
Flexing and bending can damage metals and elongated crystals.
  • Thin mica sheets can withstand some flexing.
  • Silver, copper, and gold occur as wires and sheets that are sometimes bent into more aesthetic shapes. [This is debatably a treatment that should be disclosed.] Over-bending a specimen can cause it to break.
  • Some fibers are more elastic than others. Most fibrous specimens will be damaged by "patting" them; such as the black velvet surface of some psilomelanes. Others, like pectolite, can damage the person patting them! Okenite balls are sometimes shown to children as minerals one can pet, but the fibers are much less durable than plush animals.
  • Itacolumnite, or flexible sandstone, can lose sand grains when flexed.
  • Fibrous minerals can also be damaged by being dusted. (Millerite geodes are a common example of this.) Do not let inexperienced people dust, hold, or even touch your mineral specimens without supervision.

Monday, March 14, 2011

4a. The evils that beset mineral collections: Variations in humidity

Often--but not always--correlated with changes in temperature are variations in humidity. These threaten mineral specimens by changing their solubility in air. I remember a salt crystal in the Harvard student mineral collection, then at the Science Center, that had developed a lovely set of salt rings surrounding it on the glass shelf in its display case. All the salt from the rings had originally come from the large crystal, and its faces were slightly frosted.

Changes in humidity also threaten mineral labels and boxes for soluble minerals, just as dipping the labels or boxes in salt water would attack them.

Possibly bacterial damage of specimens such as iron sulfides can be enhanced by humidity and its changes.

Most museums try to keep their humidity constant, often at about 55% relative humidity. Sometimes you see humidity chart recorders in cases or rooms.