SAND DOLLARS, SEA URCHINS and STARFISH
(Singular nouns: Fr-petit clypéastre, châtaigne de mer, & astérie/étoile de mer-?; Ger-Sand-dollar, Seeigel, & Seestern; 
 Nor-sand dollar, kråkebolle, & sjøstjerne; Rus-песок доллар, кожие-?, & морские  везды)



A. Sand dollar and replica.  Left, sand dollar (?Encope michelini L. Agassiz, 1841?) (height - 9.2 cm) collected on Gulf of Mexico beach, Port Aransas, Texas.  Right, pewter replica (height - 8 cm).  (© photos by Dick Dietrich)
                                                                                                                  
B. Sea Urchin - Left, spines of a "pencil urchin" (which one yet to be determined). (© photo courtesy of Naples Sea Shell Company;  from  http://www.naplesseashellcompany.com).  Right, cross section of echinoid spine (© photo courtesy of Fiona Meldrum, University of Bristol, Bristol, UK;  from  http://www.inchm.bris.ac.uk)


C. Starfish "collected in an area of Savannah Reef called Sow's Pen [off Atlantic coast of Georgia and South Carolina].  (photo from National Oceanic and Atmospheric Administration, U.S. Department of Commerce, http://oceanexplorer.noaa.gov/)  

DESCRIPTION: Phylum, Echinodermata:   Sand dollars and sea urchins (both - class, Echinoidea) and starfish (class,  Asteroidea) are living representatives of the phylum Echinodermata used rather widely in jewelry and decorative items.  Sea lilies (class, Crinoidea) and brittle stars (class, Ophiuroidea), also living Echinodermata, have also been used in the "decorative arts," but only rarely.  Sea cucumbers (class, Holothuroidea), another group of currently living Echinodermata, are virtually never so-used.  The hard parts of those that are used consist chiefly of magnesian-calcite with MgCO3-contents ranging between 5 and 15 per cent (Raup, 1966).
    Colors -  Sand dollars are typically off white;  most sea urchin spines used as parts of decorative items are purple or brownish purple and white;  the starfish used are typically off-white, ecru, tan or darker brown, but some of them are diverse hues of red, orange, yellow or purple or combinations thereof. 
    H. (effective hardness) 2½ - 3
    S.G. 2.65 - 2.7 (depending upon sample size and method of measurement;  the point being they are rather porous)
    Light transmission - semitranslucent to opaque
    Luster - dull to pearly to subvitreous
    Breakage - irregular
    Miscellaneous -  All echinoderms are marine animals.  Virtually all hard parts of the echinoderms treated in this entry effervesce with dilute HCl (hydrochloric acid).  The spines of echinoids that have roles in decorative items are relatively large (commonly 10 cm long), partially hollow or filled with a calcium carbonate mesh, and tend to jingle when dropped on hard surfaces or knocked against each other.  Sand dollars and sea urchins are characterized by a real or at-first-look radial (commonly five-fold) symmetry.
 
OTHER NAMES:  Names other than the common names given in the title of this entry are sometimes used for all or parts of these animals and/or their hard parts.  Examples follow:   USES:
Jewelry: Beads -- Spines of pencil urchins have been used in necklaces, both in groups and as central pendants, and for bracelets.  Columnals of sea lilies (i.e., stem sections of crinoids, class Crinoidea), which are hollow disks, have been used for necklaces.  --  Indeed, some fossil columnals that have been weathered out of rocks have been used, especially those found (and worn!) by beach combers. 
Decorations -- Sand dollars (see Figure A, Right), sea urchins and starfish have found wide use as decorative pieces and parts thereof -- e.g., of wreaths.
Mobiles -- Spines of the pencil urchin have been made into wind chimes -- usually as the "chimes."  For a few, however, these spines serve as the central weighted units with seashells as the "chimes."

OCCURRENCE  & LOCALITIES:  Echinoderms are marine and found sporadically in all oceans. 
 
REMARKS:  The designation Echinodermata stems from the Greek combining form (έχîνος) denoting something prickly and (δέρματ) -stem of δέρμα skin. (O.E.D.).

With a few exceptions, each of the skeletal units and spines of echinoderms is a single, albeit composite, magnesium-rich calcite (+ protodolomite) crystal  -- i.e., each unit consists of aggregates of microcrystals with parallel crystallographic axes (e.g., Raup, 1959 &1966;  Towe, 1967;  Schroeder et al., 1969).  The units "may articulate with one another, as in the flexible sea stars and brittle stars, ... [or be so-to-speak] fused together to form a rigid skeletal test ... in sea urchins and sand dollars. ..." (Ruppert, Fox and Barnes, 2004, p. 873).   In any case, "in the living organism, the stereom does not show the characteristic cleavages of the calcite, because of its latticed structure and the presence, in the meshes of the calcareous network, of the organic stroma." (Ubaghs, 1967, p. S14-S15).   One of the more interesting and apt descriptions follows:  "Echinoderms have been compared to living, moving castles. Castles are made of interlocking blocks, with a single main entrance and numerous slit windows for air and for defense. Echinoderm skeletons are made up of interlocking calcium carbonate plates and spines..." (The Museum of Paleontology ... University of California ...,1994).

Sand dollars are whitened by flushing them with water (in some cases with a little added bleach), dried and then coated (for example, using a sponge) with a roughly 50:50 mixture of water and white glue.  Sea urchin spines' soft tissue can be removed by treating them "with 5% sodium hypochlorite for several hours, ... [then] washed several times in water, adjusted to pH 7.3, and, finally, air dried"  OR  "removal of the stroma [may be effected] with Chlorox" (Davies, Crenshaw and Heatfield, 1972, p.876 & 877).  Starfish, once  cleaned, can be soaked in isopropyl alcohol for a few hours and then dried;  in some cases  the legs need to be weighted down so they do not curl during  the drying.

On the basis of a study of the echinoid Arbacia punctulata (Lamarck, 1816), it seems that spines of echinoids, if broken will regenerate and grow to their original lengths, even restoring their characteristic patterns (Davies, Crenshaw and Healthfield, 1972). 

One of the unfortunate things relating with some of these echinoderms is that they are seldom found where they were washed up on beaches (and virtually never, in the numbers needed to fulfill the "needs" of fashioners who use them and the marketers of the products).  Even more unfortunate is the fact that this "predicament" has led to "fishing" for live individuals, AND, several of them have become endangered species. 

SIMULANTS: Although some people might consider some of the things listed under REPLICAS to be simulants, it is my opinion that none do.  As a matter of fact, I have seen neither records nor examples of any thing that I think would qualify as a simulant rather than a replica. 
 
REPLICAS:  Molds made from sand dollars and starfish are used to cast metals and alloys -- e.g., copper, gold or silver and brass or pewter (Fig. A, right);  they are marketed widely, especially in souvenir shops near sea coasts where these natural animals are found on beaches.  Some of the casts that are used are made in molds prepared from "sculptures" of brass made from molds of the natural marine forms. Most life-size replicas are too large for adornment and consequently are used for decorative pieces for mantels, whatnots, etc.  Other replicas in this general size category , but poor because their relative dimensions are not realistic, are used for things such as Christmas tree ornaments, "starfish" that obscure wall hooks, and parts of "wall art" and wreaths;  most consist largely of glass and plastics.  A multicolored (each arm a different color) raku starfish is advertized as made by South African craftsmen.

Smaller replicas used chiefly for jewelry consist of all the just mentioned materials, but brass and gold appear to be the choices of most craftsmen who produce them;  additional materials also frequently used include gemstones (e.g., variscite) and enamels.  Most of these replicas are used on bracelets and/or as pendants, pins and dangling earrings.  An out-of-the-ordinary set, best described as rough replicas, includes a pendant/pin and matching earrings that consist largely of numerous "sparkling" faceted "stones" that are vintage jet-black glass.

Recently (2006), I saw a rather attractive, though highly stylized, starfish replica made of opal glass and marketed for use as a paperweight and, an equally attractive life-sized sea urchin-like mass made of glass that is said to include "a pinch of ash from the 1980 eruption of Mount St. Helens."   Indeed, the use of things made to resemble different echinoderms could be extended "on into the night ..." -- Think about the advertisement in a recently distributed mail-order catalog from a specialty house that featured such things as  three "Starfish sculptures" fashioned from wire mesh (the largest more than two feet across and sea urchin-shaped vases, which consist of cast resin, that are up to a foot in diameter.

Virtually two-dimensional starfish-like forms also adorn diverse items that reange from expensive leather items (e.g., bejeweled purses) to inexpensive (cheap!!) clothing (e.g., low grade T-shirts). 

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R.V. Dietrich © 2015
Last update:  28 January 2014
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