CALIFORNITE, See IDOCRASE CANCRINITE
Bright yellow to orange-yellow massive,    usually with  blue  sodalite;   seldom -
occurs large enough to provide pure-color    cabochons over i/2″ diameter;  soft,
brittle; collectors’ item only.
Ontario or Maine, massive    oz.    1.00
CARBORUNDUM, see SILICON CARBIDE CARNELIAN, See QUARTZ CASSITERITE
Bolivia, facet grade, according to size & color
Mexico, wood tin, brownish nodules
CATL1NITE
Soft,  easily  carved  stone  containing  pyrophyllite
reddish in hue; Indian “pipestone.”
South Dakota
CATSEYE SHELL, See SHELL
CELESTITE
A highly prized collectors’ item when faceted from colorless, flawless material; hard and tough but too rare to be used commercially; clear material only from outer zones of the dark brown crystals from Bolivian tin deposits. Massive fibrous variety known as wood tin sometimes cut cabochon. Faceted gems over 1-2 ct. rare; largest clean gems not
CERUSSITE
An extremely soft lead mineral, but capable of being cut into attractive faceted gems of considerable brilliance and dispersion; the best material is colorless; collectors’ item only. Also in excellent catseye material, but very rare.
CHALCEDONY, See QUARTZ CHERT, See QUARTZ CHIASTOLITE, See ANDALUSITE CHLORASTROLITE, See PUMPELLYITE CHLOROMELANITE, see JADEITE
CHONDRODITE
Excessively rare one-locality mineral from Tilly Foster iron mine, New York, as small transparent brownish-red crystals not over i/8″ thick; occasionally avail able from old collections; collectors’ gem only.
Facet grade, to 4 ct.    ct.    2.00-12.00
CHROMITE
Black, massive chrome ore, sometimes cut as a curiosity.
Maryland, California, or Oregon    lb.    2.50
CHRYSOBERYL
Very hard and durable; provides excellent gems for jewelry such as catseyes, chartreuse to yellow faceted gems, and alexandrites, the last noted for their color change from green in daylight to bright red under artificial tungsten light, the value depending on how distinct the change is, how vivid the colors, and, of course, size, freedom from flaws, etc. The finest alexandrites came from the Urals and rough is no longer obtainable; those from Ceylon tend to be brownish and display considerably less attractive colors; recently in fair to good small crystals from Brazil and as small crystals with good color change from Rhodesia. The best catseyes display a remarkably sharp silky white eye upon a highly translucent green to yellow background, the greenish hues being more desirable; also in alexandrite type but seldom showing good color change. Brownish to yellowish facet grade chrysoberyls are not highly prized commer¬cially because they resemble the cheaper gemstones, citrine and golden beryl; chartreuse-green faceted gems are much more esteemed and command good prices.
Brazil, greenish body color, add 15%-20% to above prices Brazil, alexandrite-type, weak color change, 3-4 ct.     ct.
End of Chrysoberyl Section
CIIRYSOCOLLA, See QUARTZ CI1RYSOPRASE, See QUARTZ
CITRINE, see QUARTZ CLEIOPHANE, see SPHALERITE
(XINOZOISITE
Sometimes available from Baja California as facet-grade crystals of brownish color; a collectors’ gem.
Brown to yellowish-brown, to 10 ct.    ct.    .25
COAL, see ANTHRACITE
COBALTITE
Produces interesting metallic luster cabochons of pink-silver color.
Ontario, massive pieces to i/2 lb.    lb.    2.50-4.50
COLEMANITE
Soft, fragile, and slowly perishable facet-grade crystals obtained from the bo¬rate deposits of California; collectors’ gem only.
Colorless to faint yellow, to 8 ct.       ,    ct.    .20-.75
CONCH, see SHELL
CORAL
Occurs in all shades from pale to dark pink or orange-pink, to various shades of red, to dark red (”ox-blood”); also brownish-red, and mottlings of several hues or with white; pure white is also commonly available. Mottled pieces are considered much less desirable. Flaws include worm borings and soft places, or discolorations due to decomposition in the case of coral fished up dead. Soft but fairly tough and capable of receiving fine detail in carvings and an excellent polish. Used in carvings, cabochons, beads, and as polished stem and twig sec¬tions set “as is” in jewelry or strung in necklaces in the case of slender twigs of about 1/16″ thickness. Some large branches are sold for table ornaments; especially prized and very rare are sea-floor stones upon which a handsome growth of coral is attached; however, fakes are common, consisting usually of sections of branches, sometimes polished, set into soft rock which lacks the white calcareous deposits typical of true sea-floor pebbles. Values vary widely accord¬ing to tastes developed in individual countries; pelle d’angelo, or “angel’s skin,” is highly prized in Europe and in the Orient, its color being a pure rose; also valued in the Orient is pure white, but yellowish-tinged varieties are unaccept¬able; intense pink appears to be valued by everyone, but darker hues to deep red (”ox-blood”) are more esteemed in the United States. Large masses increase sharply in value because of the considerable rarity of old but perfect coral branches. Trade  terms used  for various grades of coral  are:   Sardinian, hard material of excellent quality; Italian, good quality in all shades from white to red; Moro, a fine-quality deep red Japanese type; tosa, average Japanese coral; Sicilian and Algerian, lesser qualities of Mediterranean coral; and Japanese coral, used to designate pieces that are mottled white and red.
Black coral is a different marine organism, lacking the calcareous skeleton of the true coral; its stems and branches consist of intensely black organic matter of great toughness; supplied from Pacific waters mainly; in vogue foi black, light-weight jewelry, accepts a fine polish; thick stem sections of aboui 1″ are liable to split along annular growth rings.

CORDIERITE, See IOLITE
CORUNDUM
Includes ruby, sapphire, and star stones; red hues are called ruby but pinks and all other colors are called sapphire with the implication that the rough is suitable for gem purposes; otherwise it should be called by the species name. In recent years opaque to barely translucent red corundums have been sold as “ruby,” particularly from India; needless to say they command but a very small fraction of the price received for real ruby in equivalent sizes. Finest sapphires are intensely hued, blue being the favored color; also prized are amethystine hues, orange, and rich pink; yellows are not as desirable for jewelry purposes while most greens tend to be somewhat dingy in hue, although very fine Australian stones have been found. Best star stones show distinct six-ray stars upon a richly-colored background whether red as in ruby or blue as in sapphire; as background colors depart from these hues the values drop sharply; the most abundant and cheapest star sapphires are only faintly blue, purplish, or merely pale gray to nearly white. In terms of size, star stones reach as much as 40 cts. in ruby and several hundred cts. in sapphire; faceted rubies over sev¬eral cts. weight are rare but sapphires commonly occur in sizes of many carats. Hard, durable; a standard gemstone. Good rough always difficult to obtain be¬cause the best material in largest sizes is cut locally and only the leftovers are sold outside the country.
RUBY
The finest rubies occur in the gem gravels of Burma; good rubies also from
Thailand and pale rubies from Ceylon; very rarely, small rubies of good color
from gravel deposits  in United States and Australia.  Extremely  expensive  in
rich red color, costs increasing rapidly with size and freedom from flaws.
Burma, fine reds, if available, 1-4 ct.    ct.    10.00-100.00
“     “    “        5-6 ct.    ct.    15.00-300.00
“     “    “        7-10 ct.    ct.    20.00-600.00
“     “    “    over 10 ct.    ct.    30.00-1000.00+
STAR   RUBY
Burma, fine star, if available, 1-10 ct.    ct.    5.00-550.00+
SAPPHIRE
The best rich blue sapphires occur in the gem gravels of Burma, sometimes in sizes large enough to facet gems of several hundred carats weight; fine rich blues also occur in Thailand but are usually much smaller; fine pale blues characteristic of Ceylon gravels; very small but fine colors from Yogo Gulch, Montana; fair to good sapphires from Australia especially in yellows and greens.
SYNTHETIC   RUBY   AND   SAPPHIRE
Star boules are not commercially available, all being used to cut finished gems in behalf of designated marketing companies; facet-grade boules available in any color and in any quantity. Synthetic ruby crystals grown by Chatham are avail¬able under the name “cultured ruby”; they closely resemble natural ruby crystals in respect to properties and inclusions.
CROCOITE
Small, brilliant red-orange transparent crystals only from Tasmania; faceted gems cut from them are far too soft to be used for any purpose except as col¬lectors’ items.
Prismatic crystal sections, i/g”-1^” long    ea.    .35-.50
CROWN OF SILVER, see QUARTZ (Psilomelane Chalcedony)
CUPRITE
Very rarely, as small clear crystals suitable for faceting collectors’ gems; the term “cuprite” is commonly used to designate a cuprite-stained epidote metarhyo-lite from Pennsylvania which has some use in cabochons and ornamental objects.