Dull streaks

Helps to reduce dullness, streaking, crocking and will somewhat improve color yield. 

Cannel coal is a dull, compact, bituminous coal, that is to say it is rich in volatile hydrocarbons and bums very easily. It consists of varied plant debris, and under magnification it can be seen that it is made up of spores. It is brittle with a slightly paler sheen than that of jet and does not take such a high polish. It has a conchoidal fracture but produces a black powder when worked. It was more commonly used for large pieces than for jewellery. It leaves a black streak when mbbed against a matt surface such as unglazed porcelain. 

Celluloid was one of the early plastics that was used in numerous ways. It was made of cellulose nitrate and was extremely combustible, but a safer version, cellulose acetate, was later developed. Dyed black, they are reasonable imitations of jet but th have a plasticy look and feel. Black celluloid gives a fldnt, black streak. Baikelite, or phenol formaldehyde, could be dyed any colour and was widely used. When dyed black, it was also a reasonable jet imitation, but it dulls with age and has a plasticl look and feel. Black Bakelite gives a black streak. 

Properties Brown, black, yellow, white color luster adamantine or dull submetallic streak white. Mohs hardness 6-7, d 6.8-7.1. 

Properties Red, scarlet, reddish-brown to blackish solid, streak scarlet luster adamantine to dull earthy when impure. D 8.10, Mohs hardness 2.5. Soluble in aqua regia. Has greater optical rotation than any other substance (+325 degrees). 

Properties Brilliant black to blackish-red or brick-red mineral with brown to cherry-red streak and metallic to dull luster. D 4.9-53, Mohs hardness 6. Noncombustible. 

Properties Black mineral, black streak, submetallic or dull to metallic luster. Contains 72.4% iron. Readily recognized by strong attraction by magnet. Soluble in powder form in hydrochloric acid. Decomposes at 1538C to ferric oxide Fe203, d 4.9-5.2, hardness 5.5-6.5. 

Properties Black color, brownish-black streak, pitchy to dull luster. Mohs hardness 5.5, d 6.5-8.5. 

Properties Iron-black to dark steel-gray or bluish mineral black or bluish-black streak metallic or dull luster. D 4.73 1.86, Mohs hardness 2-2.5. Soluble in hydrochloric acid. 

Properties.—Massive structure finely granular. Brittle. H. = 5-5. G. = 5-343. Lustre dull. Colour dark gray. Streak ash-gray with slight greenish tint. 

Properties,—Amorphous, reniform or spheroidal. H. = 4. G. = 4-60-4-76. Lustre resinous, dull or earthy. CJolour white, gray, lirownish, yellowi.sh. Streak white to grayish or yellowish. 

Many problems may be encountered in thermoforming, some of these are related to plasticizers or they can be eliminated by changes in plasticizer type and amount Problems related to plasticizers include die lines or dull spots (plate-out buildup), dark specs and streaks (polymer degradation), excessive sag, distortion after part removal, warpage, poor wall thickness distribution, and part sticking to mold. 

Fully covered with white scale, 70% dull bright and 30% black. Some bright spots without scale found under washer 30% of contact area unattacked and bright. White deposits (70%) in the form of streaks Outer edge clean White deposit... 

Dawsonite [Named after the Canadian geologist John William Dawson (1820-1899), principal of McGill University, Montreal, Canada] (ICSD 100140 and PDF 42-1346) NaAl(C03)(OH), M= 144.00 15.97 wt.% Na 8.34 wt.% C 18.74 wt.% Al 1.40 wt.%H 55.56 wt.%0 Orthorhombic a = 673 pm bs 1036 pm c 558 pm P.G. 2/m2/m2/m S.G. Imam (Z= 4) Barentsite type Biaxial (-) a= 1.462 P= 1.542 Y= 1-596 5=0.130 27=76.75" Dispersion weak <3 2420 (2434) Habit thin encrustations, bladed, needle-hke or radial crystals. Color colorless to white. Diaphaneity transparent. Luster vitreous to silky. Fracture uneven. Cleavage [110] Perfect. Streak colorless. Other fluorescent under short-wavelength UV with dull white. Occurrence low-temperature hydrothermal mineral. 

Psilomelane (syn., Romanechite) [from Greek, psilos, smooth, and melanos, black, owing to the common smooth sur ce of the concretions from Roman che, Sadne-et-Loire, France] (ICSD 202692 and PDF 42-618) BaMn"Mn",0 (OH), Af = 955.74568 Coordinence Ba(lO), Mn(6) (Oxides and hydroxides) Monodinic a = 1392.9 pm b = 284.6 pm c= 967.8 pm 92.65 (2=2) P.a2/m S.G. C2/m Biaxial (aa.) R = 24.1-28.8% 5-6 (HV 503- 627) 3950- 4710 (4740) Habit massive, reniform, botryoidal, earthy, fibrous, dendritic. Color dark black to dark steel gray. Luster submetaUic to dulL Diaphaneity opaque. Streak brown to black. Qea ige none. Fracture uneven to conchoidal, brittle. Occurrence associated with cryptomelane. Note wad is a common name for a low hardness varieties, while manganomelane describes high density varieties (i.e., above 3000 kg.m ). 

Tenorite (syn., melaconite, melanochalcite) [Named after the Italian botanist, M. Tenor] (ICSD 67850 and PDF 45-937) CuO Ms 79.5454 79.89 wt.%Cu 20.11 wt.% 0 Triclinic P.G.-1 Biaxial R = 23.4% 3.5-4 (HV 209- 254) 6500 Habit scaly, earthy, massive. Color black. Luster earthy (dull). Diaphaneity opaque. Streak blade. Geavage none. Fracture conchoidal. Occurrence secondary copper mineral... 

Metallic The effects of metallic contaminants on the plated deposits and the maximum levels allowable are as follows copper darkness, 5 to 10 ppm cadmium dullness, 50 ppm zinc dullness, 50 ppm nickel streaks, 50 ppm iron dullness, 50 to 120 ppm and chromium... 

Lustro rcsuious, dull or earthy. Goloxir white, gray, brownish, yellowish. Streak white to grayish or yellowish. 

---