SGRP home page

The National Roman Fabric Reference Collection: a Handbook

Hand specimen picture panel
Thin section picture panel


Appendix 1: Keywords and Definitions
Appendix 2: Physical Layout of Sherds Housed in the NRFRC


Central Gaulish (Micaceous) Terra Rubra (CNG TR)

Four samples

Three variants with different surface treatments (red slip, mica coating and white slip) are combined together here.

General appearance

Our two red-slipped sherds are red-brown or red-orange (2.5YR 5/6–4/6) with smooth slipped surfaces, red (10R 4/8) to dull orange (5YR 6/6). Platters and drinking cups were produced in this fabric. A single cream-slipped sherd is orange-brown (5YR 5/6) with pink (10R 6/8) core and an easily abraded cream (10YR 8/3–8/4) slip. Rigby (1989a, 119) notes a thin matt underslip, although this was not visible on our sherd. In Britain flagons and lagenae of restricted typology are found in this fabric. Finally, the single mica-coated sherd is orange-brown (2.5YR 5/8) with a pale grey (6/0) core (typical of the fabric in general, Rigby 1989a, 120) and orange (near 5YR 6/8) surfaces, with abraded golden mica coating. Abrasion of the mica coating – which originally only covered the rim and part of the shoulder – is typical of the fabric, and it frequently survives only in the grooving and under the rim (ibid). The most distinctive form in this fabric is a lid-seated jar. All samples are hard with an irregular fracture.

Hand specimen

The three different surface treatments are united by fabric, which is generally ill sorted, dominated by common quartz and somewhat less feldspar measuring c 0.1–0.3mm, but ranging between <0.1–0.5mm. Mica is prominent on the surface (to 0.5mm), and although less distinctive in the break it is frequently common; in some cases silver predominates, although the actual mica coating tends to contain more gold. Sparse poorly defined rounded and subrounded brown and black clay pellets (0.3–1.4mm), as well as smaller dark iron-rich inclusions (0.1–0.3mm) and red or white clay pellets (0.1–0.5mm) are all present. These samples belong to Rigby’s (1989a, 118-120) Standard Fabric Group 1.

Thin section

Three samples – corresponding to the different surface treatments – were examined in thin section and show some variety in texture. In general however the fabric is composed of a silt-grade matrix with larger grains varying in frequency, but measuring to c 0.3mm, and composed of primarily quartz and somewhat less feldspar. All samples contain common muscovite and sparse biotite mica, together with a sprinkling of mixed ferromagnesian minerals. Rarely volcanic rock fragments (plutonic and finer) can also be identified. Opaques are visible in all sections, as are prominent clay pellets (to 1.0mm>). In a larger programme incorporating 26 samples and using the electron microprobe, Freestone (Freestone & Rigby 1986, 264) identified alkaline volcanic, plutonic and schistose metamorphic rocks, and further classified the ferromagnesian minerals as brown amphibole, clinopyroxene, rare olivine, sphene and apatite.


The area from the northern edge of the Massif Central into the Loire Valley provides a likely source area for this fabric type, although kiln evidence is lacking (Rigby 1989a, 119).


Colchester Museums; Department of Prehistoric & Romano-British Antiquities, The British Museum


Ferdière, A, & Ferdière, M, 1972 Introduction à l’étude d’un type de céramique: les urnes à bord mouluré gallo-romaines précoces, Revue Archéologique de l’Est et du Centre-Est 22, 77–89

Freestone, I C, 1989 The petrology of the pottery from the Iron Age cemetery, in Verulamium. The King Harry Lane site (I M Stead & V Rigby), Engl Heritage Archaeol Rep 12, 264–6

Freestone, I C, & Rigby, V, 1986 The petrology and typology of the earliest identified central Gaulish imports, J Roman Pottery Stud 1, 6–21

Rigby, V, 1989a Pottery from the Iron Age cemetery, in Verulamium. The King Harry Lane site (I M Stead & V Rigby), Engl Heritage Archaeol Rep 12, 112–210

See the related record on the Atlas of Roman Pottery on the Potsherd website

Plate 2: Fresh sherd break of CNG TR (width of field 24 mm). Click to see a larger version

Plate 2: Fresh sherd break of CNG TR (width of field 24 mm)

Plate 2.1: Photomicrograph of CNG TR (XPL) (width of field 1.74 mm). Click to see a larger version

Plate 2.1: Photomicrograph of CNG TR (XPL) (width of field 1.74 mm)

<< Central Gaulish (Micaceous) Terra Nigra  ::  Gallia-Belgica Craquelée Bleutée >>