Several rocks in addition to those treated as entries in this document have been fashioned into gemstones and/or ornaments. Some noteworthy examples are included in this appendix, and chemical compositions given for those that consist wholly or largely of one mineral. One or more items fashioned from each of these gemrocks are recorded in most of the cited references.
In addition, it is beyond my ken why thinsections of certain rocks -- e.g., dunites and ophicalcites -- have not been mounted between sheets of polaroid and illuminated with miniaturized backlights for incorporation into jewelry such as brooches, earrings, and pendants or as the foci of diverse ornamental objects; some of the diverse colors and patterns that would be seen are shown in Figures A and B and several more can be seen in, for example, MacKenzie, Donaldson and Guilford (1982)
A. Thinsection (field - ca. 1.5 x 1 cm) of chondrodite (praying figure mimeotolith) and phlogopite-rich area of a slide of an impure marble that occurs adjacent to the Fish Creek phacolith of Macomb township, St. Lawrence County, New York. (© photo by Dick Dietrich)
B. Thinsection (field - ca. 1.5 x 1.2 cm) of a dunite -- i.e., a rock consisting largely of the mineral olivine -- from an unrecorded locality. (© photo by Dick Dietrich)
C. Jaspilite -- banded iron formation -- outcrop at Ispeming, Marquette County, Michigan. (photo by H.L. James, courtesy of Economic Geology)| GEMROCK NAME | REFERENCE | REMARKS |
| Agalmatolite
(also called image stone, koreite or koireiite, and Qing Tian stone, etc.) |
Smith (1962, p.458) | soft rock, made up largely of talc, pyrophyllite, or "pinite" (i.e., massive muscovite that is typically clay-bearing), or some combination of these minerals; resembles soapstone; much of this rock has come from east China. See also pagodaite in this tabulation. |
| Allura | See gaspeite. | |
| "Apache
gold" |
Mueller (2012, p.67) | "neither
gold nor Apache but ... a delightful stone containing chalcopyrite and
pyrite in a black schist." from Jerome, Arizona. |
| Astorite | Muhlmeister
& Chadwick (2007, p.164-165) |
trade name
for pink (with gray bands and small brown and black patches),
rhodonite-rich rock (rhodonite, quartz and rhodochrosite, and minor
amounts of chiefly sulfides) from Toltec mine area of San Juan
Mountains of southwestern Colorado. |
| Astridite | Read (1988, p.140) | "dark green chrome-rich jadeite with lighter coloured veins and intergrown with picolite, quartz, opal and limonite ... [from] New Guinea." |
| "Atlantisite" | Laurs (2012, p.229-230) | A mixture of serpentine and Stichtite
from Tasmania. See Stichtite. |
| Azurite-antlerite rock | Kammerling & Fryer (1995, p.120) | rock consisting largely of blue azurite and green antlerite plus quartz from an unrecorded locality. |
| Banded iron
formations |
See Figure C
and jaspilite. |
|
| Barite ( Baryte -
BaSO4 ) |
Webster (1994, p.319) | brownish
speleothem barite/baryte from Devonshire. See also "oakstone." |
| Bauxite | Lui (1995, p.22) | a weathering product, composed largely of aluminum hydroxides (e.g., gibbsite and boehmite) and the major source of aluminum, this rock seems an unlikely material for use as a gemrock; bauxite beads from Togo, Africa, have, however, been reported. |
| Bayldonite ( (Cu,Zn)3Pb(AsO3OH)2(OH)2 ) | Webster (1994, p.319) | green "mammillary concretions of fibrous crystals." |
| Blue quartz ( SiO2 ) | Dietrich (1971, p.79) | blue quartz that resembles moonstone occurs as quartz "eyes" in an augen gneiss from the Little River Gneiss of Floyd County, Virginia; the fact that thequartz of these eyes are so-to-speak mylonitized (i.e., macerated) appears to account for their color and moonstone-like quality. |
| Blue schist |
Stucki (2005,
p.350-351) |
a glaucophane
schist that contains green omphacite, red garnet and white
calcite from Aosta Valley in Italy's western Alps is used
for cabochons and beads -- cf.
ecologite in this appendix.
|
| Bowesite | Kelly (1986, p.5-8) | rock made up of diverse percentages of pale green diopside, yellowish green epidote, pink-brown grossular, dark green to bluish green actinolite, nearly white andesine, colorless quartz, brownish sphene, white calcite, and black magnetite(?); rock's overall color is light to dark green with off-white mottling or streaking; from near Cracow, Queensland, Australia. |
| Bumble
Bee jasper |
Overlin,
(2014a, p.166-167) |
a black,orange, gray, and off-white
material (natural?!!) from Java that consists of a mixture of
volcanic lava and sediment (see photo in reference). |
| Campbellite |
Mueller
(2012, p.66-67) |
"assembly
of secondary minerals. It may contain two or more of the
following: calcite (much of it fluroresces red), stained calcite
(blues and greens), copper, cuprite, malachite, and turquoise, among
others." (ibid.) from Campbell Mine, Bisbee, Arizona. |
| Canalize | Arem (1987, p.61) | purplish rock, not well described, from the Khibina Tundra, of Siberia. |
| Cancrinite ( Na6Ca2(AlSiO4)6(CO3,SO4)·2H2O ) |
Koivula, Kammerling & Fritsch (1993, p.131) | a light blue, predominantly cancrinite rock that occurs in nepheline syenite dikes near the head of Kagssortoq Fjord, Greenland. |
| Carmazul (also called chrysocarmen) |
Mitchell (1985, p.40) | a red, green, blue and brown oxidized copper-rich rock made up of chalcedony, chrysocolla, hematite, jasper, malachite, and quartz from Lower California, Mexico. |
| Céruléite ( Cu2Al7(AsO4)4(OH)13.12H2O ) |
Arem (1987, p.63) | rare turquoise-blue mineral from, for example, southern Bolivia, constituting impregnated porous masses which have been used for fashioned museum pieces and gemstones. |
| Chalcosite rock | Webster (1994, p.325) | rock composed of
reddish-brown kalifeldspar, green plagioclase feldspar, grey quartz,
and black mica (biotite) from Ambatofinandrahana, Madagascar. Unfortunately, the term chalcosite has also been given only too frequently to specimens of the mineral chalcocite (Cu2S); so, in my opinion, this name should be abandonded so far as applying to this gemrock. |
| Chlorite
rock |
Covington
(2004, p.2-11) |
"Chlorite"
is the name given by
the
non-geologist writer of the cited article to what appears in illustrations
very possibly to be chlorite-rich rocks, apparently from long
abandoned
quarries in southern Iran. It was used from at least the middle
to the
late third millennium B.C. as the raw material for carving bowls,
vases,
cups and diverse decorative items. |
| Clinochlore
( (Mg,Al)6(Si,Al)4O10(OH)8 ) (marketed as Seraphinite) |
Johnson and Koivula (1996, p.130) and Evseev (1994, p.44) | green to bluish green masses with radial to irregularly shaped zones that exhibit chatoyancy from the Korschunovskoye deposit, Angara-Ilim area, Irkutsk District, east of Bratsk Reservoir, east of Lake Baikal, Siberia. |
| Cobaltocalcite ( CoCO3 ) | Liddicoat
(1967-68, p.251) |
faceted
stone that exhibits "interesting agatelike structure" from an unlisted
locality. By the by,
cobaltocalcite is a discredited mineral species. |
| Corsite
(also called napoleonite, Corsican granite and kugeldiorite) |
Webster (1994, p.361) | grayish orbicular diorite (honblende gabbro?) from Santa Lucia di Tallano, Corsica. An orbicular gabbro-diorite described by Watson, Laney and Merrill (1906) would appear also to be a potentially good gemrock. |
| Corundum
fuchsitite |
See Ruby-fuchsite-kyanite rock. | |
| Corundum,
tourmaline, kyanite rock |
Fryer et al. (1981, p.106) | an extremely attractive rose (corundum), green (tourmaline), and blue (kyanite) rock, though not recorded as having been used as a gemrock, certainly appears to have such potential. |
| Cumberlandite
|
Dietrich
(1986, p.251-257 ) |
a
titaniferous magnetite metatroctolite from Cumberland County, Rhode
Island. It is a porphyritic
appearing rock with light, off-white labradorite "phenocrysts" surrounded by black
titaniferousmagnetite,
olivine and spinel. Its use as gemrock depends chiefly on its
rarity
and its being the official state rock of Rhode Island. |
| Daisy stone | Brummer (1980, p.2375) | basalt with rosettes of feldspar from near Mamainse Point, north of Pancake Bay on Lake Superior, about 60 miles north of Sault Sainte Marie, Ontario, Canada. |
| Dickite ( Al2Si2O5(OH)4 ) | Johnson et al. (2000,p.74) | a print-block carved with the likeness of Dick Liddicoat(d), former chairman of GIA, was carved from a massive clay of the kaolinite-serpentine clay family with properties that appear best to match dickite – a great coincidence, eh?! In any case, this piece may lead to future use of this and similar claystones; see also ARGILLITE entry. |
| Dumortierite ( (Al,Mg,Fe)27B4Si12O69(OH)3 ) |
Koivula, Kammerling & Fritsch (1992, p.271) | massive dumortierite (and, more frequently, "intergrowths" of dumortierite and quartz or quartzite impregnated by dumortierite) from, for example, the Humboldt Range near Oreana, Pershing County, Nevada has been fashioned into beads and curios. Some so-called dumortierite quartz, the color of which is intense blue to greenish blue to violet blue has been marketed as California lapis. |
| Eclogite | Switzer (1945, p.1) | the recorded eclogite, which consists of sporadic masses of a red pyropic garnet surrounded by bright dark green omphacitic pyroxene surrounding scattered makes an attractive gemrock. The name eclogite, by the way, comes from the Greek meaning choice selection. |
| Eleolite (=elaeolite) | Webster (1994, p.354) | brownish red, green, gray or brown, massive or coarsely crystalline nepheline ((Na,K)AlSiO4). |
| "Emerald matrix" | Anna Stose brooch (F.S. Dietrich collection) | cabochon consists of emerald-green crystals of hiddenite (=green spodumene =lithia emerald ) within relatively fine-granular white quartz; from Spruce Pine district, North Carolina. |
| Epidote-quartz rock | See UNAKITE entry. |
|
| Eudialyte rock ( eudialyte - Na15Ca6Fe3Zr3Si(Si25O73) -- (O,OH,H2O)3(Cl,OH)2 ) |
Johnson & Koivula (1999, p.49-50) | cut and polished pieces fashioned from a eudialyte-rich rock – that also contains feldspar, fluorite, galena and tourmaline – from eastern Canada (Quebec?) are described and illustrated. |
| Feldspar +
garnet
(of grossular-andradite- uvarovite series) |
Kammerling & Fryer (1994, p.42) | snuff bottle from China is illustrated. |
| Fibrolite | . | see sillimanite. |
| Friedelite ( Mn8Si6O15(OH,Cl)10 ) | Pienaar (1982) | massive pink, carmine to orange to brownish red, translucent to subtranslucent aggregates comprise veins that transect low-grade manganese deposits of the Kalahari manganese field, near Kuruman, northern Cape Province, Republic of South Africa. |
| Fuchsite-corundum
rock ( fuchsite is a green, chromium- bearing muscovite ) |
Schultz-Güttler (2005) | spheres
etc. have been fashioned
from a fuchsite (green), corundum (red) plus white alkali feldspar rock
that contains sporadic tiny reddish orange rutile grains from Bahia,
Brazil (cf. Ruby-fuchsite-kyanite
rock in this tabulation). |
| Fuchsite-rich
rock ( fuchsite is a green, chromium-bearing muscovite ) |
Costa (2011) | thin polished slabs of a rock otherwise not described, though one microphotograph suggests it is a fine-grained schist of phillite, are described as possibly usable as fough for cabochons (although of "relatively low hardness." |
| Gaspeite ( (Ni,Mg,Fe)CO3 ) | Koivula, Kammerling & Fritsch (1994, p,126) | cabochons, beads, etc. are made from a massive yellow-green variety of this mineral, first found on the Gaspé Peninsula, Québec, Canada; also found at, for example, Kambalda and Widgie Mooltha, Western Australia – this latter material is commonly marketed as "Allura." |
| Gillespite in
sanbornite matrix |
Richard Busch
(personal communication, 2007) |
spheres and
eggs have been fashioned from this rock that consists of bright red
streaks (veinlets?) of gillespite in an off-white sanbornite matrix
from the La Madrilena mine, Baja California, Mexico. |
| Gold-bearing vein
quartz (also called butter gold and jewelry rock) |
Murphy and Modreski (2002) | "free gold dispersed in tiny crystalline aggregates and in small veinlets" in quartz veins, from Ouray and San Miguel counties is described as "one of Colorado's well-known lapidary materials ... used in jewelry." |
| Grossular ( Ca3Al2(SiO4)3 ) | Webster (1963); Maddison (1991, p.249) | diverse colors -- e.g., translucent, predominantly mottled brownish yellow massive "grosularite garnet." See also JADE entry under Simulants subheading. |
| Grossular, diopside, vesuvianite (etc.) rock |
Kamerling & Fryer (1994, p.186) | white grossular and green rock from northern Washington (state). |
| Gummite | Pough (1996, p.158) | this yellowish and/or orangy rock -- which has a characteristic waxy luster and consists of diverse combinations (complexes!) of silicates and salts of uranium plus water -- occurs in, for example, pegmatites of the Spruce Pine district of North Carolina and the Ruggles Mine, New Hampshire. By the way, gummite is best described as an "omnibus term." |
| Halite ( NaCl ) | see rock salt. | |
| Howlite ( Ca2B5SiO9(OH)5 ) | "Dictionary of gems and gemology ... " (GIA, 1974) | often dyed and used as a simulate for, for example, turquoise, howlite "is in demand for making bookends, spheres, ashtrays and similar ornamental and utilitarian articles. ... Outstanding localities are Nova Scotia and Tick Canyon, near Saugus, Los Angels Co., California." |
| Hydrogrossular ( Ca3Al2(SiO4)3 (OH)4 ) | McClure & Kammerling (1992, p.264) and Hurwit (in Moses, Reinitz McClure, 2000, p.63-64). | as massive polycrystalline masses -- e.g., a carving made from translucent, chiefly pink hydrogrossular, and a green carving and a strand of pink and green beads -- all marketed as rare jade. |
| Jambolite (trade name based on popular Swahili greeting jambo) |
Hanni (2008, p.266-267) | massive
polycrystalline masses consisting largely of feldspar, quartz and
muscovite that are either blue (said to resemble lapis lazuli) because
of the presence of abundant veinlets of azurite OR greenish (said to
resembe chrysocolla) because of the presence of malachite and
chrysocolla. |
| Jaspilite
(also called banded iron formation, jasper bar, etc.) |
personal observations | this rock, which consists of alternating bands of massive gray specular hematite and red jasper that are sporadically contorted and/or brecciated; occurs in many places -- e.g., in the Marquette Iron Range of Michigan and near Coppin Gap, West Australia and Tuena, New South Wales, Australia. (cf. Tiger iron under Other Names subheading in HAWK'S-EYE entry.) |
| Kakortokite | Webster (1994, p.347) | an arfvedsonite (nearly black) nepheline (off-white) syenite that contains sporadic red eudialyte grains from the southern bank of Kangererdluarssuk Fjord, Julianebab district, southern Greenland. |
| Kikkaseki (= stone of chrysanthemum flower) |
Ishihara (1986) | a metamorphic rock that contains radial clusters of carbonate minerals from Japan. See Figure C in PORPHYRY entry. |
| Koranna stone
(also called South African wonderstone) |
D.R.Cristy (personal communication, 1998) | pyrophyllite-rich rock; see Figure C in SOAPSTONE entry. |
| Larimar | See pectolite. | |
| Laterite | Moore (2001) | nodules, referred to as "ochre" -- natural holes in the rock are used for stringing if this rock as beads in West Africa. |
| Lazulite ( (Mg,Fe)Al2(PO4)2(OH)2 ) | Smith (1962, p.448) | massive
fine-grained varieties. See scorzalite
in the tablation. |
| Lepidolite
( K(Li,Al)3(Si,Al)4O10(F,OH)2 ) (a mica) |
Arem (1987, p.124) | granular or massive, pink to lilac colored lepidolite from, for example, California pegmatites. |
| Manganese-bearing
mica to here |
Koivula, Kammerling & Fritsch (1993, p.210) | massive reddish purple pinitic mica originally tentatively identified, perhaps incorrectly, as lepidolite because of its associated pegmatitic minerals. |
| Mansfieldite ( AlAsO4·2H2O ) | Koivula, Kammerling & Fritsch (1992, p.201) | photo in referenced article indicates it would be more properly termed mansfieldite matrix. |
| Mica-rich rocks | Webster (1994, p.383) | examples are verdite, which consists laregly of a green mica (chrome muscovite or fuchsite) from Zimbabwe and Transvaal, South Africa, and rocks such as the green marble of Shrewsbury from the Green Mountains, near Shrewsbury, Vermont and selwynite of the Heathercote area, Victoria, Australia. |
| Mimetite ( colloidal
(Pb5(AsO4)3Cl) ) |
Hyrsl (2013, p.123.) | "rock" that, especially when it has a banded agatelike appearance, is sometimes fashioned into cabochons. The locality from which the described specimen came is unknown, but thought to be Bolivia (Hyrsl, op.cit.) (cf. schalenblende and wood tin) |
| Miskeyite | Mitchell (1985, p.130) | name given to a compact chlorite-rich rock, from St.Gallenkirh, Vorarlberg, Austria |
| Mojave stone | Cooke (1982, p.2340) | "a potpourri of brochantite, antlerite, albite, bisbeeite, linarite, hematite, jasper, barite and other minerals. Native copper is sometimes found in the stone, as well as silver and even gold. ... A hallmark of the most unusual material is the unique pattern resulting from crystal pseudomorphs ... [which makes] the stone a symphony of brilliant blues and greens with accents of red, black and brown." |
| Myrickite | Mitchell (1985,p.134) | “Trade name for a gray to white chalcedony or agate containing red inclusions of cinnabar from San Bernardino County, California. Although opal containing cinnabar has also been named myrickite, the preferred name is opalite.” Some is said (Hyršl (2012, p.57-58) to resemble Chicken-bloodstone; see also Rosalinda in this Table. . |
| Nebula stone | Jones (1998, p.64) | trade name for a dark green rock that contains golden green spheroidal masses (the "nebula") from Mexico; the rock, which consists largely of quartz and anorthoclase (feldspar) plus noteworthy riebekite and aegirine, is described by S.A. Williams (1997 p.c. to Ron Nurnberg) as a quartz pantellerite. |
| Oakstone | Mitchell (1985, p.140) | "Brown, compact, banded stalactitic barite rock that has been polished and used for fashioning ornaments; occurs at Arbor Low, near Youlgreave, Derbyshire, England" cf. barite/baryte. |
| Okkolite | See UNAKITE entry. | |
| Opal matrix (matrix opal) | Keeling & Farrand (1984) | two kinds: 1.fractured opal "healed" with some other material and 2.fragmented (e.g., breciated) rocks with opal matrices. Some of the latter rocks have also been called boulder opal or given their appropriate rock name and noted as opaline. Examples are recorded from Virgin Valley, Clark County, Nevada; Anda-mooka, South Australia (matrix opal); Lightning Ridge, Ceara', Brazil; Honduras; and Mexico. |
| Orthopyroxene rock | Koivula, Kammerling & Fritsch (1993, p.282) | a "life-size" carved mask of this material is illustrated in the referenced article; l descriptive information about its composition and origin are not given. |
| Pagodaite | Smith (1962, p.458) | name given agalmatolite (q.v.) used in China for carving pagodas etc. |
| Papagoite | Arem (1987, p.144) | massive mixtures
of papagoite ( CaCuAlSi2O6(OH)3 )-- and quartz from the vicinity of Elko, Nevada. |
| Patricianite | MacFall (1983, p.136) | mixture of green chlorite with veinlets of prehnite and native copper flecks from northern Michigan. |
| Pectolite
( NaCa2Si3O8(OH) ) |
Woodruff and Fritsch (1989) | compact massive greenish blue, gray, and white, translucent to opaque pectolite that occurs as cavity fillings and veins in altered basalts. That called larimar is from the Hispanola Mountains of the Dominican Republic; that called Alaska jade from near Point Barrow, Alaska. Aragonite, with the trade name victorite, from Oquegua, Peru has been marketed as a pectolite simulant. |
| Phosphosiderite ( FePO4 · 2H20 ) | http://www.mindat.org/min-3187. html |
jewelry -- e.g.
beads, earrings, and pendants apparently fashioned from massive
lilac-colored phosphosiderite have been marketed. I have not
examined any of these. The web site given in column 2 gives data
about the mineral. |
| Pinite ( massive muscovite - KAl2(Si,Al)4O10(OH,F)2 ) |
Fryer et al. (1983, p.175) | example recorded is a floral motif carving that consists of white pinite, mottled with light and dark brown, and bears an oriental inscription. |
| Plagioclase and muscovite rock | Kane (1985, p.173) | example recorded is a predominantly white (plagioclase) and green (muscovite) carving of a bell. |
| Planchéite
(+?shattuckite) (planchéite -Cu8(Si4O11)2(OH)4·H20 ) |
Webster (1994, p.372) | compact masses of granular and/or fibrous blue plancheite as such or impregnating, for example, quartz from Bisbee, Arizona. |
| Prehnite | Hurlbut & Switzer (1979, p.205) | green and blue-green prehnite, especially that in stellate groups -- see also THOMSONITE entry. |
| Pyrophyllite ( Al2Si4O10(OH)2 ) | See Agalmatolite and
also the SOAPSTONE entry. |
|
| Pyroxmangite (MnSiO3 ) | Murphy and Modreski (2002) | massive pyroxmanganite from San Juan County, Colorado has been slabbed and made into, for example, cabochons. |
| Quartz-schorl
intergrowth |
Dietrich (1985, p.115) | colorless to smoky quartz with black tourmaline rods, the arrangement of which resembles that of graphic granite; potentially a fine gemrock. |
| Rock salt ( Halite - NaCl ) |
Kemper(1999, p.78) | diversely colored
salt blocks, typically used as cow licks, rather than natural rock salt
-- have been carved to resemble such things as bowls, bottles and other
decorative items. In addition, added
9 April 2005, ammended 1 February 2008: Catalogs of some
specialty houses, market diverse articles (e.g.,
bowls, carvings and lamps) said to have been fashioned from "Natural
Salt formed
millions of years
ago..." |
| Rosalinda |
Hyršl (2012, p.57-58) |
a scapolite (marialite) - Mn-epidote
(epidote-piemontite) rock, commonly also calcite- and
grossular-bearing from near Tambo Colorado, Peru; said to
resemble Chicken-bloodstone. |
| Rubasse (also termed rubace and rubacelle) |
Mitchell (1985, p.172) | this is red, predominantly quartz rock, the color of which depends upon numerous hematite inclusions is from Brazil. |
| Ruby matrix | Koivula, Kammerling & Fritsch (1994, p.274) | ruby crystals within a matrix of white plagioclase feldspar from Myanmar (formerly Burma). |
| Ruby-fuchsite-kyanite
rock |
Milisenda
(2003, p.124) |
a
colorful light red and green (+
sporadic gray-blue kyanite zones) gemrock from India (e.g., Mysore); O'Briens Claims, Zimbabwe; and
Mashishimala, South Africa that has
been fashioned into cabochons, freeforms and ornaments. (see also
Quinn, 2004a.) |
| Schalenblende (colloidal
sphalerite -- (
(Zn,Fe) S ) |
Hyrsl (2013,p123) |
"rock" that, when it
has an agatelike appearance, is sometimes fashioned into
cabochons. The name is its usual German designation. It is
wdespread,
especially important localities are in Poland and Bolivia (Hyrsl,
op.cit.) (cf. mimetite and wood tin) |
| Scorzalite
(
(Fe,Mg)Al2(PO4)2(OH)2 ) |
Liu (1995, p.14) | rock consisting largely of this deep blue mineral of the lazulite group (used for a bead from Mauritania, West Africa). |
| Selwynite | . | see Mica-rich rocks. |
| Seraphinite | . | see Clinochlore. |
| Serpentine-forsterite
(olivine) rock |
Kammerling & Fryer (1994, p.189) | example shown is
a horse carving; forsterite is an olivine. |
| Shattuckite ( Cu5(SiO3)4(OH)2 ) | Arem (1987, p.171) | massive blue material from the Shattuck Mine, Bisbee, Arizona. |
| Shrewsbury
(green marble of...) |
. | see Mica-rich rocks. |
| Sillimanite ( Al2OSiO4 ) | Spencer (1971, p.223) | compact masses of fibrous sillimanite, sometimes termed fibrolite, have been used as a jade substitute. |
| Siltstone |
Amos (2005) |
"A sculpted and polished phallus found in a German cave...the famous Hohle Fels Cave near Ulm in the Swabian Jura...was reassembled from 14 fragments of siltstones." |
| Skarn | Kammerling, Koivula & Fritsch (1995, p.64) | tan and green striped rock, with apatite, hedenburgite and wollastonite as its noteworthy constituents. |
| Spurrite ( Ca5(SiO4)2(CO3) ) | Wentzell (2004, p. 63) |
purple, chiefly spurrite rock
from Guerrero State, southern Mexico. |
| Stichtite
( Mg6Cr2CO3(OH)16·4H2O ) |
Smith (1962,
p.459); see also Koivula et al. (2003, p.221) and
Laurs (2012, p.229-230) |
lilac- and
rose-pink, chiefly stichtite rock with sporadic green or yellow-green
serpentine occurs near Dundas, Tasmania, Australia, and "gem-quality
stictite," some of which has a texture
described as micro-oolitic texture, is
recorded from Canada and South Africa. Some of the relatively recently
fashioned material is marketed as "Atlantisite." |
| Tuff | Murphy et al. (2000) | tuff (i.e., lithified pyroclastic materials) of diverse compositions were used in, for example, "jewelry manufacturing centers" in the Caribbean region during Pre-Columbian times. See Appendix D. |
| Tugtupite
( Na4BeAlSi4O12Cl ) |
Arem (1987, p.193) | massive tugtupite of diverse colors from Greenland. |
| Ulexite
( NaCaB5O6·5H2O ) (also called "television stone") |
Arem (1987, p.196) | masses of this silky white mineral have been fashioned into cat's-eye cabochons; in addition, it would seem that ulexite, as a so-to-speak-topping (i.e., protection) mounted over for, for example, a picture, would lead to rather interesting effects and thus have a good potential as a gemrock, especially for brooches. |
| Verdite | . | see Mica-rich rocks. |
| Violane | Smith (1962, p.60) | massive violet-blue pyroxene from Switzerland; also said to be a blue-purple diopside from San Marcello, Valley of Aoste, Italy. |
| Willemite, calcite, zincite, franklinite rock | personal collection | A paper weight, for example, of this greenish (willemite), white (calcite), red (zincite), black (franklinite) rock from Franklin Furnace, New Jersey is rather attractive and a great conversation piece when exhibited under ultra-violet radiation. Arem (1987, p.208) characterizes cabochons, apparently made of this material under zincite as "extremely beautiful as well as highly fluorescent" although zincite is not the fluorescent component. |
| Wollastonite
( CaSiO3 ) |
Koivula & Kammerling (1989, p. 49) | compact, massive off-white to greenish gray or yellowish brown, and rarely reddish, subtranslucent wollastonite-rich rocks -- some of which contain minor amounts diopside, titanite and one or more of the feldspars -- , typically with a matte-like lusters; from the Viola mining district, about 50 miles east of Caliente, Lincoln County, Nevada; also a reddish material is from Isle Royale, Lake Superior. (cf. skarn) |
| Wood tin (colloidal cassiterite -- SnS2 ) | Hyrsl (2013,p123) | "rock" that is sometimes fashioned into cabochons. It is wdespread; especially important localities are in Mexico and Bolivia (Hyrsl, op.cit.) (cf. mimetite and schalenblende) |
| Yalakomite | Mitchell (1985, p.216) | "local name for a decorative stone composed of magnesite and quartz, with an attractive coloration imparted by pink jasper and green chromian phengite (mariposite)" from area northwest of Lillooet, British Columbia. |
| Zonochlorite |
Merrill
(1922) |
name
once given to masses thought to be chlorastorlite but now recognized as
largely, if not
wholly,
prehnite; from the Lake Superior region the north-central United
states
and adjoining Canada (cf. Prehnite on this table). This is a doubly unfortunate
designation: it is not a chlorite and it appears to have been applied
originally to chlorastrolite per se
as well as to those masses now known to be chiefly prehnite. |
R. V. Dietrich © 2015
Last
updated: 11 December 2014
web page created by Emmett Mason