More information provided by NAU American Southwest Virtual Museum:

Estrella Red-on-gray is the earliest type of Hohokam Buff Ware.  This type was produced primarily in the middle Gila River valley and in Queen Creek, but is found as far south as the Tuscon area.

Archaeological Culture: Hohokam

Date Range: ca. A.D. 500-600.

Construction: By paddle and anvil.

Firing: In a neutral to oxidizing atmosphere; fire clouds common.

Temper: Mica, schist, and quartz.

Surface Finish: Fire clouded or sooted; many are polished, with mica obvious on the surface; non-porous; incised types smoothed on the interiors only. Red slip is present on some bowls. Polishing is over the paint, smearing the lines, on some vessels

Paste Color: Typically gray, brown, or gray-brown; dense.

Forms: Bowls predominate; some jars; few effigies.

Decoration:

• Paint: Bright red, dull red, or purplish red; sometimes smeared from polishing, and some applied with a finger rather than a brush.


• Pigments: Iron oxide mineral paint.


• Design: Wide line work; quartered layouts with nested straight-line hachure fill and chevrons common; rare small element layouts (curvilinear scrolls and commas). Bowls frequently decorated on both the interior and exterior; primary design field usually the interior. Trailing lines are absent.


• Incising: Coil-based; regular and continuous incising (bowls).

Key Traits: Line width greater than 6.0 mm; presence of exterior red slip or wash; polishing over the painted design; coil-based incising; gray or brown paste with fire-clouded surface.

Comparisons: Beyond provenance, Estrella Red-on-grey is essentially indistinguishable from contemporaneous red-on-brown types. Later Sweetwater Red-on-gray has hachure-sectioning and is rarely slipped.

Oppelt (2007:123): Estrella Red-on-gray (Ca. AD 500s) This is the first painted Hohokam Buff Ware type. The designs are done in broad lines and are usually quartered. Designs are mainly straight lines and nested chevrons. Some appear to have been applied with the finger. The temper is varying proportions of mica schist and quartz fragments. Some small bowls have grooved exteriors. Estrella Red-on-gray was made by the paddle and anvil method and fired in an oxidizing atmosphere. The forms of this type include bowls and jars and a few effigies.