Estimating the Age of Whale Teeth from Natural Dry-Out Cracks
This guide outlines one basic method used to estimate the age of authentic whale teeth. Scrimshaw collectors are always interested in knowing whether a whale tooth is:
Antique = more than 100-years old (>100-yo);
Vintage = (50-yo to 100-yo); or
Modern = less than 50-years old (<50-yo).
Other, more complicated factors (NOT discussed here) are involved in narrowing or confirming the age of whale ivory.
All whale teeth have a natural skirt at the base of a tooth, which protects the living nerve root. Young teeth have a blade-thin & knife-sharp skirt edge [CLICK on Image #1]. In contrast, the tooth skirt of teeth from old whales can be short & thick, or nearly non-existent [Image #2]. Most antique scrimshawed whale teeth were taken from mature Sperm whales, where as most vintage & modern scrimshawed whale teeth were taken from any Sperm whale within reach of a harpoon gun. It is probable that more teeth were scribed from 1950 through 1982, than in the 150-years prior, and most of these latter teeth were 8-ounces or less. In all of the following images, note that size differences often reflect age differences.
Any tooth NOT “in situ” (original mouth location) immediately begins to dry-out. Two symptoms are surface hardening (becoming brittle) and cracking (due surface shrinkage). With age, both characteristics become more pronounced.
For Sperm whale teeth, the surface hardening happens within a few months of removal from the whale. Victorian-era scrimshanders working on fresh teeth could easily use common tools at hand, such as pocket knives & sail needles, on the soft-surfaced teeth. Contemporary scrimshanders use razor-sharp Xacto blades and needle-sharp tungsten scribing tips. Even then, scribed lines on the brittle surface of an aged whale tooth [Image #3] are actually a series of linked, minute, shatter-pits, just like scratching glass.
In whale teeth, “age-cracking” progresses very slowly, and may take decades before becoming apparent. A thin tooth skirt may show age-cracking years before a more stout tooth from the same whale. Using dry-out cracks to determine age is only a guide, and does not take into account environmental conditions prior to evaluation. To counter dry-out cracking, I store all of my scrimshawed whale teeth in a hermetically-sealed glass display case, with a shot-glass of water inside.
Victorian-era scrimshanders cut-off a 1/2-inch (or more) of the skirt edge. This left a blunted, thicker lip, which physically resists dry-out cracking, and allowed the whale tooth to stand, or self-display vertically. On antique whale teeth, these blunted skirt edges often display a “crazed” cracking pattern [Image #4]. Losing a 1/2-inch on a 7-inch tooth is nearly negligible, but modern scrimshanders most often scribe 4-inch to 6-inch teeth, and purposely do not shorten teeth for any reason.
a whale tooth skirt with NO dry-out cracks is considered to be <25-yo [Image #1];
a whale tooth skirt with one or two small, fine, dry-out cracks is <50-yo [Image #5];
a whale tooth skirt with several dry-out cracks is 50-yo to 100-yo [Image #6];
a whale tooth with multiple dry-out cracks, and/or “crazing” is >100-yo [Image #4 & Image #7].
Dry-out age cracking can also be observed across the median line between the hard core-tip (Dentine) aka Golden Crown, and the outer layer (Cementum) [Image #8]. The line count is roughly the same as for the tooth skirt.
Displaying or storing a whale tooth in an excessively dry environment can cause premature cracking, or accelerate existing cracks. Once a crack reaches 1/3 to 1/2 length of tooth, it has the very real potential of reaching the tip, and even meeting another crack from the other side, cleaving the tooth in half.
Patina (tooth color) naturally deepens with age, but is also heavily influenced by environmental conditions. A tooth stored in a drawer for 100-years could be just as ivory-white as a new tooth. On the other hand, a 25-year old tooth displayed on the open shelf in the home of a smoker could have deep, rich, brown patina from the absorption of tar from cigarette smoke. A similar color can be obtained (or enhanced) by immersion in tea or coffee. Usually, only in-hand evaluation can reveal false patinas, so a written guide on patina is not as useful as this guide on dry-out cracking. Correctly assessing the age of a whale tooth through properly interpreting both dry-out cracking and patina, depends on accumulated experience as much as knowledge. The more whale teeth you view, the more experience you will acquire. And remember: you can NEVER see too many whale teeth.