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Theodosius

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    Let's see some lions!

    in General

    Posted

    A bit different one:

    image.png.1224a90cdb28af1fb0d5dca282762886.png

    Seljuqs Of Rum, Kaykhusru II, (Giyath Al Din) 634-644 AH / 1236-1245 AD
    AR Dirham, 2.92 grams, 22mm, Struck At Sivas, In 637 AH.
    Obverse: Sun And Lion Motif
    Reverse: Inscription.
    References: Album Type 1218, Mitchiner Mwis-982.
    John

    • Like 14

    Let's see some lions!

    in General

    Posted

    Similar lion scalp:

    image.png.b2bc48f47bbfac1df4bb72b38c897b15.png

    Perikles. Circa 380-360 BC
    AR Third Stater, 3.01 grams, 16-17mm
    Obverse: Lion scalp facing.
    Reverse: Triskeles; in one section, draped bust of Hermes, wearing winged petasos, facing slightly left
    References: SNG von Aulock 4256 var. (position of Hermes)

    John

    • Like 14
    • Heart Eyes 1

    Let's see some lions!

    in General

    Posted

    One of my favorite lion coins:

    image.png.b10449a692525d31d198744046dcbf8a.png

    Islands off Ionia, Samos
    AR Didrachm, 6.57 grams, 310-300 BC. 
    Obverse: Lion scalp
    Reverse: NANISKOS, Forepart of an ox charging right, SA, olive spray.
    References: Barron 22,6. HGC 1229. 
    Ex Jean Elsen Brussel V, 1981
    Very rare.     

    John

    • Like 15
    • Heart Eyes 3

    Much Ado About Nothing?

    in General

    Posted

    A lot depends on the average humidity of the location you live. Bronze disease is much more active when the humidity level is over 50%. If you live in Florida where the average humidity is 60-80% then it is a real problem.

    It is also a problem when a coin was discovered in a dry, desert location like Egypt the Middle East etc and then made its way to someone in a very humid climate, then there is a chance that bronze disease will become active.

    Bronze disease does not turn into hard green patina. It is a catalyzed reaction, the chlorine atoms causing it are not consumed by the reaction, they catalyze it. So they are never used up. If left untreated in humid conditions bronze disease will cause a lot of damage and never stop. The only way to stop it is to neutralize the chlorine atoms by binding them to some stable chemical like a base, or removing them through distilled water soaks and scrubbing.

    I too have bronze coins I bought 40 years ago that are still fine despite living in Florida the whole time. Usually it is new coins coming to me that reveal they have a problem after 6 months or a year. As Doug points out how they were cleaned has a lot to do with it too. If the original protective patina is damaged and bare metal is exposed that contains chlorine atoms then look out if you live somewhere humid.

    John

    • Like 5

    The Anders Collection - Who Is Anders?

    in Greek

    Posted

    I think Ken nailed it. The anonymous person names are not about auction houses trying to drive up the value of the coins, it's about the collector themselves taking pride in seeing their coins presented in a public venue. The collector knows who "Anders" is and when he or she want to look up their old collection they have a way to do it.

    I agree that sometimes auction houses make up fictitious horde or collection names as a marketing ploy, but those usually have a Hollywood exaggeration to them that makes them easy to spot.

    John

    • Like 4

    the Bronze disease thread

    in General

    Posted

    The fact that some commercial companies put a (probably very small) amount of benzotriazole in their products does not mean it is safe to handle the pure form.

    To treat bronze disease with benzotriazole you dissolve the solid in reagent grade ethyl alcohol. Using watered down alcohol defeats the purpose of the treatment to a large degree.  Let's look at how safe pure benzotriazole is from the Material Safety Data Sheet:

    The MSDS for benzotriazole:

    https://www.fishersci.com/store/msds?partNumber=AAA1542318&productDescription=BENZOTRIAZOLE%2C+99%+(ASSAY)+50G&vendorId=VN00024248&countryCode=US&language=en

    Here are hazards they list:

    2. Hazard(s) identification
    Classification
    This chemical is considered hazardous by the 2012 OSHA Hazard Communication Standard (29 CFR 1910.1200)
    Label Elements
    Signal Word
    Warning
    Hazard Statements
    Harmful if swallowed
    Causes serious eye irritation
    Company 
    Alfa Aesar
    Thermo Fisher Scientific Chemicals, Inc. 30 Bond Street
    Ward Hill, MA 01835-8099
    Tel: 800-343-0660
    Fax: 800-322-4757
    Email: tech@alfa.com
    www.alfa.com
    Acute oral toxicity Category 4
    Serious Eye Damage/Eye Irritation Category 2
    Precautionary Statements
    Prevention
    Wash face, hands and any exposed skin thoroughly after handling
    Do not eat, drink or smoke when using this product
    Wear eye/face protection
    Eyes
    IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing
    If eye irritation persists: Get medical advice/attention
    Ingestion
    IF SWALLOWED: Call a POISON CENTER or doctor/physician if you feel unwell
    Rinse mouth
    Disposal
    Dispose of contents/container to an approved waste disposal plant
    Hazards not otherwise classified (HNOC)
    Toxic to aquatic life with long lasting effects
    3. Composition/Information on Ingredients
    Component CAS-No Weight %
    1,2,3-Benzotriazole 95-14-7 98+
    4. First-aid measures
    General Advice If symptoms persist, call a physician. Eye Contact Rinse immediately with plenty of water, also under the eyelids, for at least 15 minutes. Get
    medical attention. Skin Contact Wash off immediately with plenty of water for at least 15 minutes. Get medical attention.
    Inhalation Remove to fresh air. If breathing is difficult, give oxygen. Get medical attention.
    Ingestion Clean mouth with water and drink afterwards plenty of water. Get medical attention if
    symptoms occur.     Most important symptoms and
    effects
    None reasonably foreseeable.
    Notes to Physician Treat symptomatically

     

    How about reagent grade Ethyl Alcohol?  It evaporates very quickly so the fumes are hard to avoid without a fume hood. The vapor is toxic. It is also extremely flammable and is absorbed through the skin.

    The MSDS for Ethyl Alcohol:

    https://fscimage.fishersci.com/msds/95414.htm

    Section 3 - Hazards Identification

    EMERGENCY OVERVIEW
    Appearance: Not available. Flash Point: 18.3 deg C.
    Danger! Poison! Causes severe eye irritation. Causes respiratory tract irritation. Flammable liquid and vapor. May be fatal or cause blindness if swallowed. Vapor harmful. This substance has caused adverse reproductive and fetal effects in humans. May be absorbed through intact skin. May form explosive peroxides. May cause central nervous system depression. May cause liver, kidney and heart damage. Cannot be made non-poisonous. Causes moderate skin irritation.
    Target Organs: Kidneys, heart, central nervous system, liver, gastrointestinal system, cardiovascular system, eyes.

    Potential Health Effects
    Eye: Causes severe eye irritation. May cause painful sensitization to light. May cause chemical conjunctivitis and corneal damage.
    Skin: Causes moderate skin irritation. May be absorbed through the skin. May cause cyanosis of the extremities.
    Ingestion: May be fatal or cause blindness if swallowed. May cause gastrointestinal irritation with nausea, vomiting and diarrhea. May cause systemic toxicity with acidosis. May cause central nervous system depression, characterized by excitement, followed by headache, dizziness, drowsiness, and nausea. Advanced stages may cause collapse, unconsciousness, coma and possible death due to respiratory failure.
    Inhalation: Inhalation of high concentrations may cause central nervous system effects characterized by nausea, headache, dizziness, unconsciousness and coma. Causes respiratory tract irritation. May cause visual impairment and possible permanent blindness. May cause narcotic effects in high concentration. Vapors may cause dizziness or suffocation.
    Chronic: Prolonged or repeated skin contact may cause defatting and dermatitis. May cause reproductive and fetal effects. Laboratory experiments have resulted in mutagenic effects. Animal studies have reported the development of tumors. Prolonged exposure may cause liver, kidney, and heart damage.

     

    So now let's take these two chemicals and mix them together, then soak some of our coins in them.  Do it outside at least with proper protection.

    I think I will pass because there are safe alternatives available.

    John

    the Bronze disease thread

    in General

    Posted

    Benzotriazol is extremely toxic. Read the material safety data sheet on it if you are interested. I would not mess with it unless you're working in a fume hood you're wearing goggles and you have gloves on. And then how much fun you going to have handling your coin after that? Using simple bases is a much safer way to treat bronze disease.

    John

    • Like 1
    • Gasp 1

    It's arrived

    in Greek

    Posted

    Thank goodness you finally got it!

    That would have been tragic if it got lost and ended up in a dumpster or some postal yahoo stole it.

    One of my all time favorite types.

    John

    • Like 2
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